24,120 results on '"RAMAN effect"'
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2. Shedding light on evolution of Raman line shape with probing laser power: Light-induced perturbation in electron–phonon coupling.
- Author
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Rambadey, Omkar V., Kumar, Kailash, Nain, Ritu, Kumar, Anil, Sagdeo, Pankaj R., Chamberlin, Philip M., and Adu, Kofi W.
- Subjects
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ELECTRON-phonon interactions , *SILICON nanowires , *LASERS , *RAMAN scattering , *RAMAN spectroscopy , *RAMAN effect , *SURFACE temperature , *PHONONS - Abstract
The laser power mediated changes in the Raman line shape have been considered in terms of interference between discrete phonon states ρ and the electronic continuum states ϰ contributed by Urbach tail states. The laser-induced effects are treated in terms of the increase in the surface temperature and thereby the scaling of electronic disorder, i.e., Urbach energy, which can further contribute to the electron–phonon interactions. Therefore, the visualization of this effect is attempted analytically as a perturbation term in the Hamiltonian, which clearly accounts for the observed changes with laser power. This has been investigated based on the experimental results of laser power dependent Raman spectra of bulk EuFeO3 and silicon nanowires, which are found to provide convincing interpretations. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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3. Pressure-induced optical anisotropy of HfS2.
- Author
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Antoniazzi, Igor, Woźniak, Tomasz, Pawbake, Amit, Zawadzka, Natalia, Grzeszczyk, Magdalena, Muhammad, Zahir, Zhao, Weisheng, Ibáñez, Jordi, Faugeras, Clement, Molas, Maciej R., and Babiński, Adam
- Subjects
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PHASE transitions , *ANISOTROPY , *RAMAN scattering , *RAMAN effect , *HYDROSTATIC pressure , *PRESSURE - Abstract
The effect of pressure on Raman scattering (RS) in bulk H f S 2 is investigated under hydrostatic and non-hydrostatic pressure conditions. The RS line shape does not change significantly in the hydrostatic regime up to P = 9.6 GPa, showing a systematic blueshift of the spectral features. In a non-hydrostatic environment, seven peaks appear in the spectrum at P = 7 GPa, which dominate the RS line shape up to P = 10.5 GPa. The change in the RS line shape manifests a pressure-induced phase transition in H f S 2. The simultaneous observation of both low-pressure (LP) and high-pressure (HP) related RS peaks suggests the coexistence of two different phases over a wide pressure range. It is found that the HP-related phase is metastable and persists during the decompression cycle down to P = 1.2 GPa, while the LP-related features eventually recover at even lower pressure. The angle-resolved polarized RS performed under P = 7.4 GPa revealed a strong in-plane anisotropy of both the LP-related A 1 g mode and the HP peaks. The anisotropy is related to the possible distortion of the structure induced by the non-hydrostatic component of the pressure. The results are explained in terms of a distorted P n m a phase as a possible pressure-induced phase of H f S 2. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Pressure-induced optical anisotropy of HfS2.
- Author
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Antoniazzi, Igor, Woźniak, Tomasz, Pawbake, Amit, Zawadzka, Natalia, Grzeszczyk, Magdalena, Muhammad, Zahir, Zhao, Weisheng, Ibáñez, Jordi, Faugeras, Clement, Molas, Maciej R., and Babiński, Adam
- Subjects
PHASE transitions ,ANISOTROPY ,RAMAN scattering ,RAMAN effect ,HYDROSTATIC pressure ,PRESSURE - Abstract
The effect of pressure on Raman scattering (RS) in bulk H f S 2 is investigated under hydrostatic and non-hydrostatic pressure conditions. The RS line shape does not change significantly in the hydrostatic regime up to P = 9.6 GPa, showing a systematic blueshift of the spectral features. In a non-hydrostatic environment, seven peaks appear in the spectrum at P = 7 GPa, which dominate the RS line shape up to P = 10.5 GPa. The change in the RS line shape manifests a pressure-induced phase transition in H f S 2. The simultaneous observation of both low-pressure (LP) and high-pressure (HP) related RS peaks suggests the coexistence of two different phases over a wide pressure range. It is found that the HP-related phase is metastable and persists during the decompression cycle down to P = 1.2 GPa, while the LP-related features eventually recover at even lower pressure. The angle-resolved polarized RS performed under P = 7.4 GPa revealed a strong in-plane anisotropy of both the LP-related A 1 g mode and the HP peaks. The anisotropy is related to the possible distortion of the structure induced by the non-hydrostatic component of the pressure. The results are explained in terms of a distorted P n m a phase as a possible pressure-induced phase of H f S 2. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Gold-grafted melamine sponge as surface-enhanced Raman spectroscopy substrate for enzyme-linked immunoassay of mycotoxins in cereal samples.
- Author
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Huang, Xianzhi, Xia, Ling, and Li, Gongke
- Subjects
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SERS spectroscopy , *MYCOTOXINS , *SUBSTRATES (Materials science) , *RAMAN effect , *GOLD nanoparticles , *MELAMINE , *FUSARIUM toxins - Abstract
Gold-grafted melamine sponge (AuSp) was fabricated and applied as surface-enhanced Raman spectroscopy (SERS) substrate for enzyme-linked immunoassay of 2 typical mycotoxins, zearalenone (ZEN) and T-2 toxin. The gold nanoparticles were in situ grown on the sponge, and the product showed good effect in enhancing Raman signal and good stability. COMSOL and Gaussian simulations were used to analyze the enhancing effect. Some of the experimental conditions that may affect the determination results were studied in order to meet the maximum response to mycotoxins. At optimized conditions, the limits of detection of the method were 1 μg·kg−1 and 0.05 μg·kg−1 for ZEN and T-2 toxin, with linear ranges of 5–100 μg·kg−1 and 0.1–20 μg·kg−1, respectively, and relative standard deviations lower than 7.0%. The established method was used to determine ZEN and T-2 toxin in six kinds of cereal samples, the recoveries were 85–120%, and relative errors were less than 13.0%. These results indicated the accuracy of the established method. After 1-year storage, signal strength of AuSp for mycotoxins determination decreased by less than 10%, showing stability over a long time. Our work provided a new method for SERS determination of mycotoxins, which reduces the complexity of substrate preparation and the sample consumption compared with traditional methods, and thus has potential for on-line SERS determination. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Impact of the host lattice on crystallographic, Raman, optical, and luminescent properties on the terbium ion.
- Author
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Ansari, Anees A. and Khan, M. A. Majeed
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IONS , *RAMAN effect , *RAMAN spectroscopy , *CRYSTAL defects , *OPTICAL properties - Abstract
A comparative study of the Gd2O3:Tb and Y2O3:Tb nanoparticles (NPs) was presented to examine the influence of the host lattices on the crystallographic phase, surface characteristics, optical properties, Raman effect, and photoluminescence properties. Cubic shapes Gd2O3:Tb and Y2O3:Tb NPs with an estimated crystalline size of 17 and 11 nm were recorded from the X‐ray diffraction pattern, respectively. Comparative absorption spectra of both oxides NPs were presented to examine the dispersibility, colloidal stability, and optical behavior of the NPs. Energy bandgap values were estimated to monitor the optical characteristics of the metal oxides in the UV/Vis region. Fourier transform infrared was recorded to confirm the surface‐attached water and organic moieties. The Raman spectra of metal oxides were recorded to examine the symmetrical dis‐order and polarizability of the vibrational bands. The ionic radius of the atoms distorts the bond structure resulting in it greatly influenced the vibrational bands of the materials. The emission spectra certified the effective doping of the luminescent Tb3+‐ion in the metal oxide host lattices. Raman spectra and emission spectra validated the crystal symmetry imperfections; subsequently, the efficiency of the Raman active modes and emission transitions was greatly influenced. In a comparative analysis, Y2O3:Tb NPs exhibited higher luminescence intensity in comparison with the Gd2O3:Tb NPs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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7. The Interaction of Matter and Radiation: The Physics of C.V. Raman, S.N. Bose, and M.N. Saha: Part 2: Physics Highlights.
- Author
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Choudhuri, Arnab Rai
- Subjects
RAMAN effect ,PARTICLES (Nuclear physics) ,BRITISH occupation of India, 1765-1947 ,PHYSICAL sciences ,UNIVERSITY faculty - Abstract
Three extraordinary physics discoveries were made in colonial India, which did not have any tradition of research in modern physics: Saha ionization equation (1920), Bose statistics (1924), and Raman effect (1928). All three discoverers were founding faculty members of the new small physics department of Calcutta University, which started functioning in 1916. These discoveries were all on the general topic of interaction between matter and radiation. In Part 1 (published in Resonance, Vol.29, No.11, pp.1557–1571, 2024), we have described the social and intellectual environment in which these discoveries were made. Now, in Part 2, we shall first present a background of the revolutionary developments taking place in physics at that time. Then, we shall provide a non-technical account of the three discoveries and point out the kind of impact these discoveries had in the subsequent development of physics. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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8. One‐Pot Polyol Syntheses of Ag Right Bipyramids and Nanocubes, and their Surface‐Enhanced Raman Scattering Properties.
- Author
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Zhu, Zhaoxi, Wang, Xiaolu, Li, Dan, Ou, Changgongyao, Liu, Ruochen, Lin, Taifeng, and Guo, Fu
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RAMAN effect , *RAMAN scattering , *SUBSTRATES (Materials science) , *ENVIRONMENTAL monitoring , *SERS spectroscopy , *FOOD safety , *SILVER - Abstract
Camphorquinone (CQ)‐mediated one‐pot polyol methods are developed to synthesize silver right bipyramids and nanocubes. Morphology control between silver right bipyramids and nanocubes is conducted by adjusting FeCl3 concentration. Silver right bipyramids with an average size of 170 nm and a yield of 87% are obtained with 0.11 mm FeCl3, while silver nanocubes with an average size of 120 nm and a yield of 70% are obtained with 0.04 mm FeCl3. The as‐synthesized Ag right bipyramids and nanocubes fabricate Surface‐enhanced Raman scattering (SERS) substrates with good signal reproducibility to detect the Rhodamine 6G with concentrations down to 10−12 m. The SERS performance of silver right bipyramids larger than 100 nm is experimentally investigated. A comparison of the Raman enhancement effect between Ag right bipyramid and nanocube is conducted by comparing the enhancement factors of as‐fabricated Ag right bipyramid and nanocube SERS substrates. The Ag right bipyramid and nanocube SERS substrates are obtained at the same experimental condition, and their enhancement factors are calculated to be 3.11 × 104 and 2.37 × 104, respectively. The fabricated sensitive SERS substrates can potentially be used for ultrasensitive detection of analytes in applications such as food safety and environmental monitoring. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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9. Effect of Deuteration on Raman Scattering in Single Crystals of Potassium Alum.
- Author
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Avakyants, L. P., Skrabatun, A. V., and Pyatyshev, A. Yu.
- Subjects
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RAMAN scattering , *SINGLE crystals , *HYDROGEN bonding , *RAMAN effect , *STRUCTURAL stability - Abstract
ABSTRACT Raman spectra of KAl(SO4)2·12H2O and KAl(SO4)2·12D2O crystals in the range of 10–4000 cm−1 were experimentally obtained and studied. An increase in the number of sulfate ions, oriented by oxygen atoms towards the K+ ion, was detected upon deuteration of the sample. Low‐intensity Stokes components ν = 2485 cm−1 (ν = 1820 cm−1 for the deuterated crystal) were recorded, which indicates the formation of hydrogen bonds O–H•••SO42− (O–D•••SO42−), where the donors are water molecules of the [Al(H2O)6]3+ complex and the oxygen atoms of the sulfate ion act as acceptors. The decrease in the wavenumbers of internal vibrations of the sulfate ion during deuteration was explained by an increase in the strength of hydrogen bonds. The results obtained indicate the direct influence of deuteration on the degree of initial disordering of sulfate ions and on the stability of the crystal structure of potassium alum. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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10. Advances in the clinical application of Raman spectroscopy in breast cancer.
- Author
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Ma, Mingyue, Zhang, Jiangbo, Liu, Ying, Wang, Xin, and Han, Bing
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RESONANCE Raman spectroscopy , *BREAST cancer surgery , *RAMAN effect , *SPECTRAL imaging , *BREAST cancer research - Abstract
Recently, Raman spectroscopy has made phased progress in clinical research of breast cancer. Raman spectroscopy is a nondestructive optical analysis technology that can quickly provide biochemical molecular specific information of samples. The analysis of Raman spectral characteristics at different stages of clinical activity in breast cancer patients is helpful to formulate individualized diagnosis and treatment plans, improve surgical results, adjust treatment strategies, and promote prognosis. Due to the development of optical technology and the diversity of clinical research needs, derivative Raman techniques based on Raman effect have emerged, such as surface-enhanced Raman spectroscopy, resonance Raman spectroscopy, spatial shifted Raman spectroscopy and coherent Raman scattering spectroscopy. In this paper, the research progress of Raman spectroscopy and its derivative techniques in the diagnosis and treatment of breast cancer in recent years is reviewed. The diagnostic value of different Raman techniques in different levels of breast cancer cells, body fluids and breast tissue and microcalcification molecules is evaluated. In addition, the application status and prospects of Raman spectroscopy and its derivative techniques in breast cancer surgery, chemotherapy and radiotherapy are analyzed and discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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11. The Interaction of Matter and Radiation: The Physics of C.V. Raman, S.N. Bose, and M.N. Saha: Part 1: Historical Background.
- Author
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Choudhuri, Arnab Rai
- Subjects
RAMAN effect ,BRITISH occupation of India, 1765-1947 ,UNIVERSITY faculty ,SCIENTIFIC discoveries ,SOCIAL context - Abstract
Three extraordinary physics discoveries were made in colonial India, which did not have any tradition of research in modern physics: Saha ionization equation (1920), Bose statistics (1924), and Raman effect (1928). All three discoverers were founding faculty members of the new small physics department of Calcutta
1 University, which started functioning in 1916. These discoveries were all on the general topic of interaction between matter and radiation. In this Part (Part 1 of a two-article series), I describe the social and intellectual environment in which these discoveries were made. Part 2 will focus on the science involved in these discoveries. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
12. Photothermal‐boosted flexible rechargeable zinc‐air battery based on Ni‐doped Mn3O4 with excellent low‐temperature adaptability.
- Author
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Guo, Wengai, Gu, Fan, Chen, Qilin, Fu, Kexuan, Zhong, Yuqing, Lv, Jing‐Jing, Pan, Shuang, and Chen, Yihuang
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RAMAN effect ,ELECTRONIC equipment ,SURFACE reconstruction ,STORAGE batteries ,ELECTRIC conductivity - Abstract
As a promising flexible energy source for next‐generation emerging electronic devices, the temperature adaptability and low‐temperature performance retention of flexible zinc‐air batteries (ZABs) remain a great challenge for their practical application. Herein, we report photothermal‐promoted aqueous and flexible ZABs with enhanced performance under a wide temperature range via using Ni‐doped Mn3O4/N‐doped reduced graphene oxide (denoted as Ni‐Mn3O4/N‐rGO) nanohybrids as bifunctional electrocatalysts. Upon being exposed to near‐infrared light, the Ni‐Mn3O4/N‐rGO exhibited a powerful photothermal effect, resulting in localized and immediate heating of the electrode. Such effects led to increased active sites, improved electrical conductivity, enhanced release of bubbles, and promoted surface reconstruction of the electrode catalyst as corroborated by simulation and operando Raman. Consequently, the catalytic performance was boosted, manifesting a superior activity indicator ΔE of 0.685 V with excellent durability. As expected, the corresponding photothermal‐assisted rechargeable ZABs possessed an excellent maximum power density (e.g., 78.76 mW cm−2 at −10°C), superb cycling stability (e.g., over 430 cycles at −10°C), and excellent flexibility from 25°C to subzero temperature. Our work opens up new possibilities for the development of all‐climate flexible electronic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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13. Numerical Investigation of Raman-Assisted Four-Wave Mixing in Tapered Fiber Raman Fiber Amplifier.
- Author
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Huang, Shanmin, Zhang, Yang, Hao, Xiulu, Fan, Chenchen, Chen, Xiao, Ye, Jun, Yao, Tianfu, Zhang, Hanwei, Huang, Liangjin, Leng, Jinyong, Xu, Jiangming, Pan, Zhiyong, and Zhou, Pu
- Subjects
RAMAN effect ,RAMAN scattering ,FIBERS ,WAVELENGTHS ,FIBER lasers ,SIGNALS & signaling ,FOUR-wave mixing - Abstract
The generation of unwanted higher-order Raman effects is the main factor restricting the power scaling of Raman fiber amplifiers (RFAs). This phenomenon arises from an interplay of physical processes, including stimulated Raman scattering (SRS), four-wave mixing (FWM), and the intricate temporal and spectral dynamics. Tapered fibers have demonstrated excellent nonlinear effects suppression characteristics due to the varying core diameter along the fiber, which is widely used in ytterbium-doped fiber lasers. In this paper, a comprehensive numerical investigation is conducted on the core-pumping tapered fiber RFAs considering Raman-assisted FWM. The higher-order Raman power in the tapered fiber is always kept at a low level, showing a weak Raman-assisted FWM effect. A numerical investigation is conducted to study the impact of the tapering ratio, the lengths of the thin part, tapered region, and thick part on the higher-order Raman threshold of RFAs. Furthermore, the impact of phase mismatch variations caused by changes in the seed wavelength, on the output signal power and nonlinear effects is analyzed. This paper presents, for the first time, a study on core-pumped RFAs using tapered fibers, providing a novel perspective on enhancing the power of RFAs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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14. 3D Digital Holography Investigations of Giant Photostriction Effect in MAPbBr3 Perovskite Single Crystals.
- Author
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Liu, Dong, Wu, Jialin, Lu, Ying‐Bo, Zhao, Yiyang, Jiang, Xianyuan, Wang, Kai‐Li, Wang, Hao, Dong, Liang, Cong, Wei‐Yan, Chen, Hao, Ning, Zhijun, Wang, Zhao‐Kui, Guan, ChengBo, Wu, Zhongchen, and Ling, Zongcheng
- Subjects
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RAMAN spectroscopy , *X-ray diffraction , *SINGLE crystals , *RAMAN effect , *POWER spectra - Abstract
The photoinduced physics always is a critical but controversial question for the new optoelectronic materials of halide perovskites. A high‐quality MAPbBr3 single crystal is grown and the lattice expansion induced by variable power X‐ray irradiation is investigated.A photoinduced deformation measurement system utilizing the off‐axis holography technique is developed and constructed to measure and illuminate the global photo‐induced deformation of MAPbBr3. Under a 473 nm laser with a power of 50 mW, MAPbBr3 exhibits an average maximum relative deformation of 1.27 × 10−3, demonstrating its remarkable photosensitivity and robust geometric response capabilities. Digital holography reveals photostriction as a localized phenomenon, reflecting the localization effect of the photogenerated carriers. The energetic and spatial transitions of those photogenerated carriers weaken the interatomic forces and in turn straighten the Pb─Br─Pb frameworks, expanding the lattice. This geometric change and the corresponding electronic impact are verified by Raman spectra, photoluminescence measurements, and first‐principle calculations. The methods and results are significant for future research on light‐induced phenomena in perovskites and other solid materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Theoretical Study on Transverse Mode Instability in Raman Fiber Amplifiers Considering Mode Excitation.
- Author
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Huang, Shanmin, Hao, Xiulu, Li, Haobo, Fan, Chenchen, Chen, Xiao, Yao, Tianfu, Huang, Liangjin, and Zhou, Pu
- Subjects
RAYLEIGH scattering ,STIMULATED Raman scattering ,RAMAN effect ,RAMAN lasers ,FIBER lasers - Abstract
Raman fiber lasers (RFLs), which are based on the stimulated Raman scattering effect, generate laser beams and offer distinct advantages such as flexibility in wavelength, low quantum defects, and absence from photo-darkening. However, as the power of the RFLs increases, heat generation emerges as a critical constraint on further power scaling. This escalating thermal load might result in transverse mode instability (TMI), thereby posing a significant challenge to the development of RFLs. In this work, a static model of the TMI effect in a high-power Raman fiber amplifier based on stimulated thermal Rayleigh scattering is established considering higher-order mode excitation. The variations of TMI threshold power with different seed power levels, fundamental mode purities, higher-order mode losses, and fiber lengths are investigated, while a TMI threshold formula with fundamental mode pumping is derived. This work will enrich the theoretical model of TMI and extend its application scope in TMI mitigation strategies, providing guidance for understanding and suppressing TMI in the RFLs. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
16. Raman-assisted Kerr platicon and perfect soliton crystal formation in the cavity.
- Author
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Wang, Xinyu, Zhang, Haoyu, Dong, Kegong, Chu, Qiuhui, Lin, Honghuan, and Wang, Jianjun
- Subjects
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STIMULATED Raman scattering , *RAMAN effect , *CRYSTALS , *RAMAN spectroscopy , *RAMAN scattering - Abstract
In this paper, we investigate the soliton evolution dynamics influenced by the stimulated Raman scattering effect. The strong Raman gain ensures the breathing platicon and stable platicon formation at the cavity with normal quartic dispersion. The switching waves benefitted from the power transformation between pump mode and Raman gain spectrum could modulate the temporal waveform at the breathing platicon existence region. The oscillated characteristics of the temporal waveform mainly rely on the central frequency of the Raman gain spectrum. Meanwhile, at the anomalous quadratic dispersion regime, the Raman effects could capture the perfect soliton crystal formation which provides one novel method for the implementation of the harmonic mode-locking process. Our findings provide a viable way to demonstrate the cavity soliton dynamics and soliton-based applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
17. Selective incorporation of antimony into gallium nitride.
- Author
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Liu, Yujie, Navid, Ishtiaque Ahmed, Mi, Zetian, and Kioupakis, Emmanouil
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LIGHT emitting diodes , *OPTICAL spectra , *LIGHT absorption , *RAMAN spectroscopy , *RAMAN effect - Abstract
Dilute concentrations of antimony (Sb) incorporation into GaN induce strong bandgap bowing and tunable room-temperature photoluminescence from the UV to the green spectral regions. However, the atomistic details of the incorporation of Sb into the GaN host remain unclear. In this work, we use first-principles calculations to understand the thermodynamics of Sb substitution into GaN and its effect on the optical and Raman spectra. Although it is empirically considered that Sb is preferentially incorporated as an anion (Sb3−) into the N sublattice, we demonstrate that Sb can also be incorporated as a cation (Sb3+, Sb5+) into the metal sublattice. Our thermodynamic analysis demonstrates that SbN0, SbGa2+, and SbGa0 can co-exist under Ga-rich conditions in n-type samples. We further confirm the dual incorporation of Sb by calculating the vibrational frequencies of different anionic and cationic substitutions to explain the origins of experimentally observed additional Raman peaks of Sb-doped GaN. Moreover, the calculated band structures of different Sb substitutions into GaN explain the experimental photoluminescence and optical absorption spectra. Overall, our analysis suggests that the coexistence of Sb3−, Sb3+, and Sb5+ substitutions into GaN explains the totality of experimental measurements. Our results demonstrate that the selective incorporation of Sb into GaN (and potentially other group-V elements such as As, P, or Bi) by tuning the growth conditions can drastically modify the electronic properties, for applications in visible light emitters and photocatalysis. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
18. Insights into the Origins of Solar‐Assisted Electrochemical Water Oxidation in Allotropic Co5.47N/CoN Heterojunctions.
- Author
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Liu, Sirui, Gao, Qiong, Geng, Bo, Wu, Lili, Xu, Zhikun, Ma, Xinzhi, Liu, Shijie, Li, Boquan, Zhang, Mingyi, Zhang, Lirong, and Zhang, Xitian
- Subjects
PHOTOTHERMAL effect ,PHOTOELECTRIC effect ,OXYGEN evolution reactions ,RAMAN effect ,OXIDATION of water - Abstract
Solar irradiation can efficiently promote the kinetics of the oxygen evolution reaction (OER) during water splitting, where heterojunction catalysts exhibit excellent photoresponsive properties. However, insights into the origins of photoassisted OER catalysis remain unclear, especially the interfaced promotion under convergent solar irradiation (CSI). Herein, novel allotropic Co5.47N/CoN heterojunctions were synthesized, and corresponding OER mechanisms under CSI were comprehensively uncovered from physical and chemical aspects using the in situ Raman technique and electrochemical cyclic voltammetry method. Our results provide a unique mechanism where high‐energy UV light promotes the Co3+/4+ conversion process in addition to the ordinary photoelectric effect excitation of the Co2+ material. Importantly, visible light under CSI can produce a photothermal effect for Co2+ excitation and Co3+/4+ conversion, which promotes the OER significantly more than the usual photoelectric effect. As a result, Co5.47N/CoN (containing 28% CoN) obtained 317.9% OER enhancement, which provides a pathway for constructing excellent OER catalysts. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
19. Improving the Performance of Bidirectional Communication System Using Second-Order Raman Amplifiers.
- Author
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Feng, Zhongshuai, He, Peili, Li, Wei, Hu, Kaijing, Tong, Fei, and Su, Xingrui
- Subjects
RAYLEIGH scattering ,TELECOMMUNICATION systems ,RAMAN effect ,BACKSCATTERING ,SCALABILITY ,SIGNAL-to-noise ratio - Abstract
In order to achieve low-cost scalability, the same-wavelength bidirectional (SWB) fiber communication system is a better solution. We present a detailed investigation of the performance of the different orders Raman amplifiers in same-wavelength bidirectional fiber communication systems. We discuss how to suppress the main factor affecting system performance which is Rayleigh scattering noise (RSN). By using different Raman amplifiers to construct different quasi-lossless transmission, the performance changes in the same-wavelength bidirectional fiber optic communication system were studied. On this basis, multi-channel and same-wavelength single fiber bidirectional system experiments were conducted to compare the performance of second-order Raman systems and first-order Raman systems. The results indicate that the Rayleigh scattering suppression effect of second-order Raman systems is better, and compared to first-order Raman systems, the average signal-to-noise ratio (SNR) can be increased by 2.88 dB. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
20. Aerosol optical properties within the atmospheric boundary layer predicted from ground-based observations compared to Raman lidar retrievals during RITA-2021.
- Author
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Liu, Xinya, Alves Gouveia, Diego, Henzing, Bas, Apituley, Arnoud, Hensen, Arjan, van Dinther, Danielle, Huang, Rujin, and Dusek, Ulrike
- Subjects
ATMOSPHERIC boundary layer ,PARTICLE size distribution ,REMOTE sensing ,BOUNDARY layer (Aerodynamics) ,LIDAR ,RAMAN effect - Abstract
In this study, we utilised ground-based in situ measurements of the aerosol chemical composition and particle size distribution, along with meteorological data from the European Centre for Medium-Range Weather Forecasts (ECMWF), to predict vertical profiles of aerosol optical properties, including the aerosol scattering coefficient, backscatter coefficient, extinction coefficient, and lidar ratio. The predicted ambient profiles were compared to retrievals by a multi-wavelength Raman lidar during the Ruisdael Land–Atmosphere Interactions Intensive Trace-gas and Aerosol (RITA) campaign in the Netherlands in 2021 for 26 time periods of approximately 1 h each. Predicted and retrieved extensive aerosol properties (scattering, backscatter, and extinction coefficient) were comparable only approximately 35 % of the time, mostly under the condition of well-mixed boundary layers. In this case, ground-based measurements can provide a way to extend extinction profiles to lower altitudes, where they cannot be retrieved, and to verify the lidar-measured profiles. Accurate representation of hygroscopic growth is required for adjusting the dry size distribution to ambient size distribution, and the estimated relative humidity profile may have a substantial influence on the shape of the calculated profiles. On the other hand, the lidar ratio profiles predicted by ground-based data also compared reasonably well to the retrieved lidar profiles (starting at 800 m) for conditions where the predicted and retrieved backscatter profiles differed considerably. The difference in the predicted and retrieved lidar ratio is usually less than ±30 %. Our study thus shows that, for well-mixed boundary layers, a representative lidar ratio can be estimated from ground-based in situ measurements of chemical composition and dry size distribution. This approach offers a method of providing lidar ratios calculated from independent in situ measurements for simple backscatter lidars or at times when Raman lidar profiles cannot be measured (e.g. during the daytime). It only uses data that are routinely available at aerosol measurement stations and is therefore not only useful for further validating lidar measurements but also for bridging the gap between in situ measurements and lidar remote sensing. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
21. Size effects of gold nanoparticles on activities of cellulose nanofiber-textured SERS substrates.
- Author
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Chen, Ruoyang, Qu, Yixiao, Ma, Zhengyuan, Wang, Jun, and He, Hui
- Subjects
SERS spectroscopy ,SUBSTRATES (Materials science) ,GOLD nanoparticles ,RAMAN effect ,SURFACE texture - Abstract
Evaporation deposition of gold nanoparticles (AuNPs) on a glass surface textured by cellulose nanofibers (CNFs) provides an effective substrate for surface-enhanced Raman spectroscopy (SERS). The performance enhancement of such a SERS substrate hinges upon the quality and quantity of nanostructured surfaces, which are strongly correlated to the AuNP particle size. Unfortunately, the size effect of AuNPs on the Raman activity of CNF-textured SERS substrates remains unclear. Here, we investigate the Raman activity of CNF-textured SERS substrates constructed by evaporating sessile drops of AuNPs with diameters of 40 nm and 16 nm on CNF-textured surfaces, respectively. Both experimentation and computation analysis reveal that the use of 40 nm AuNPs exhibits more effective Raman activity and traps larger amounts of analyte molecules than 16 nm AuNPs. Moreover, the existence of the CNF-textured surface significantly enhances the Raman signals of analyte molecules in all regions of SERS substrates when compared with AuNPs deposited on the bare glass surface. These findings provide insights into the particle size selection for fabricating effective SERS substrates and advance applications of CNF-textured SERS substrates. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
22. Tunable resonance Raman scattering of quantum dots in a nonlinear excitation regime.
- Author
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Zhang, Butian, Wang, Kexin, Song, Xinxin, Zhang, Youwei, Chen, Xue-Wen, and Wang, Shun
- Subjects
- *
RESONANCE Raman effect , *QUANTUM scattering , *QUANTUM dots , *RAMAN effect , *EXCITED states , *RAMAN scattering , *FERMI level , *POWER density - Abstract
Controllable tuning of electron–phonon coupling strength and excited state dynamics is important for the understanding of resonance Raman scattering in low-dimensional semiconductors. Here, we report a significant and reversible field-induced modulation in absolute resonance Raman intensity of quantum dots using ionic liquid gating. Meanwhile, a potential-dependent nonlinear relationship is present between Raman intensity and excitation power density. By exploring the parameter space within a time domain model, we find that the Raman intensity variation is mainly determined by the homogeneous linewidth. We further propose that the Fermi level positions and exciton species play key roles in the excited state decay rates. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
23. Electron kinetic effects in back-stimulated Raman scattering bursts driven by broadband laser pulses.
- Author
-
Liu, Q. K., Deng, L., Wang, Q., Zhang, X., Meng, F. Q., Wang, Y. P., Gao, Y. Q., Cai, H. B., and Zhu, S. P.
- Subjects
LASER pulses ,RAMAN effect ,HOT carriers ,PLASMA waves ,ELECTRONS ,RAMAN scattering ,BRILLOUIN scattering - Abstract
We examine electron kinetic effects in broadband-laser-driven back-stimulated Raman scattering (BSRS) bursts using particle-in-cell simulations. These bursts occur during the nonlinear stage, causing reflectivity spikes and generating large numbers of hot electrons. Long-duration simulations are performed to observe burst events, and a simplified model is developed to eliminate the interference of the broadband laser's random intensity fluctuations. Using the simplified model, we isolate and characterize the spectrum of electron plasma waves. The spectrum changes from a sideband structure to a turbulence-like structure during the burst. A significant asymmetry in the spectrum is observed. This asymmetry is amplified and transferred to electron phase space by high-intensity broadband laser pulses, leading to violent vortex-merging and generation of hot electrons. The proportion of hot electrons increases from 6.76% to 14.7% during a single violent burst event. We demonstrate that kinetic effects profoundly influence the BSRS evolution driven by broadband lasers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
24. Raman Effect During Formation of the Ordered L10 -FePd Phase.
- Author
-
Shkarban, R. A., Leonov, D. S., Natalenko, M. Yu., Verbytska, T. I., Barabash, M. Yu., and Makogon, Iu. M.
- Subjects
MAGNETIC structure ,RAMAN effect ,RAMAN scattering ,STRUCTURAL dynamics ,HYDROGEN atom - Abstract
ffect of the hydrogen heat treatment compared with vacuum annealing in the temperature range of 500–700C on the formation of the ordered L1
0 -FePd phase and variations in Raman spectra of the equiatomic FePd films are studied. The hydrogen atoms introduced into the nanoscale FePd films change the electronic structure and magnetic properties and states of the film. Ordering processes are accelerated under hydrogen treatments compared with vacuum annealing. By changing of parameters of the hydrogen annealing of the FePd film, it is possible to control the phase composition, ferromagnet ←→ paramagnet-variation in the magnetic states. The Raman spectroscopy allows investigate the dynamics of structural changes in the FePd films during the ordering and the ordered L10 -FePd-phase formation. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
25. Magnetic field mapping along a NV-rich nanodiamond-doped fiber.
- Author
-
Filipkowski, Adam, Mrózek, Mariusz, Stępniewski, Grzegorz, Ficek, Mateusz, Pysz, Dariusz, Gawlik, Wojciech, Buczyński, Ryszard, Wojciechowski, Adam, and Klimczak, Mariusz
- Subjects
- *
OPTICAL fiber detectors , *MAGNETIC fields , *MAGNETIC field measurements , *MAGNETIC resonance , *LASER pumping , *OPTICAL fibers , *ELECTRON field emission , *RAMAN effect - Abstract
Integration of NV−-rich diamond with optical fibers enables guiding quantum information on the spin state of the NV− color center. Diamond-functionalized optical fiber sensors have been demonstrated with impressive sub-nanotesla magnetic field sensitivities over localized magnetic field sources, but their potential for distributed sensing remains unexplored. The volumetric incorporation of diamonds into the optical fiber core allows developing fibers sensitive to the magnetic field over their entire length. Theoretically, this makes distributed optical readout of small magnetic fields possible, but does not answer questions on the addressing of the spatial coordinate, i.e., the location of the field source, nor on the performance of a sensor where the NV− fluorescence is detected at one end, thereby integrating over color centers experiencing different field strength and microwave perturbation. Here, we demonstrate distributed magnetic field measurements using a step-index fiber with the optical core volumetrically functionalized with NV− diamonds. A microwave antenna on a translation stage is scanned along a 13 cm long section of a straight fiber. The NV− fluorescence is collected at the fiber's far end relative to the laser pump input end. Optically detected magnetic resonance spectra were recorded at the fiber output for every step of the antenna travel, revealing the magnetic field evolution along the fiber and indicating the magnetic field source location. The longitudinal distribution of the magnetic field along the fiber is detected with high accuracy. The simplicity of the demonstrated sensor would be useful for, e.g., magnetic-field mapping of photonics- and/or spintronics-based integrated circuits. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
26. Isotopic effect of oxygen on the Raman mapping of a polycrystalline uranium dioxide UO2.
- Author
-
Gaillard, Clotilde, Sarrasin, Lola, Panetier, Clémentine, Pipon, Yves, Ducher, Roland, and Moncoffre, Nathalie
- Subjects
- *
URANIUM , *RAMAN effect , *RAMAN spectroscopy technique , *URANINITE , *RAMAN spectroscopy , *SPACE groups - Abstract
Uranium dioxide (UO2) is a widely studied material due to its use as fuel in pressurised water reactors (PWR), and Raman spectroscopy is a technique of choice to characterise the evolution of its microstructure. UO2 crystallises in a fluorite CaF2 (space group Fm‐3m) structure that gives rise to a unique Raman signature, the T2g band. However, several other bands are often detected whose attribution remains unclear. The present study gives new insights on the Raman spectrum of UO2 thanks to the combination of isotopic labelling with 18O and Raman imaging. In addition to the expected T2g, U2 (LO), 2LO and U3 bands, we have detected a doublet at 885 and 925 cm−1, a U* band at 555 cm−1 in some specific areas and two bands located at 367 and 1196 cm−1. All Raman bands shift under the effect of the replacement of 16O by 18O, excepting for the U* band that could not be detected anymore. The isotopic shift ratio could be determined for 20% and 30% 18O labelling. No discrepancy in band position is observed between grains and grain boundaries, except for the U2(LO) band. We also evidence a difference between the U defect bands and the 885 and 925 cm−1 doublet bands evolution under labelling, although the latter also seems to be connected to the presence of defects in the material. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
27. Raman spectroscopy of NiMo catalysts supported on solid oxides. A review.
- Author
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Flores-Aguilar, Juan Francisco, Ibarra, Israel Samuel, Guevara-Lara, Alfredo, and Vázquez-Garrido, Isaí
- Subjects
- *
CATALYST supports , *RAMAN effect , *DEGREE of polymerization , *OXIDES , *CATALYSTS , *ALUMINUM oxide - Abstract
The NiMo supported on alumina catalysts used by refineries in hydrotreatment reactions are characterized by different techniques that describe the properties of the NiMoS active phases. Raman Spectroscopy permits identify the degree of polymerization of the precursors of the active phases according to the vibrational modes of the different Mo species. The objective of this review is study the support effect on the Raman band shift and the molybdenum polymerization degree. The review commences with a background on catalysis and its application in hydrotreating reactions. Afterward, the characterization techniques for supported NiMo catalysts and the advantages of Raman Spectroscopy are discussed. Subsequently, the main Raman bands used in the assignment of the vibrational modes of the different Mo species in NiMo catalysts supported on alumina are reported. In the main section, the effects of partial or total replacement of the alumina support with Mg, Ti, Mn, Si, Zn, Ce oxides, and others, are discussed. Posteriorly, some studies are revised in which the activity of different catalysts is correlated with the results obtained by Raman Spectroscopy. To conclude, recent and future applications of Raman spectroscopy in the characterization of supported NiMo catalysts are also presented. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
28. Isotopic effect of oxygen on the Raman mapping of a polycrystalline uranium dioxide UO2.
- Author
-
Gaillard, Clotilde, Sarrasin, Lola, Panetier, Clémentine, Pipon, Yves, Ducher, Roland, and Moncoffre, Nathalie
- Subjects
URANIUM ,RAMAN effect ,RAMAN spectroscopy technique ,URANINITE ,RAMAN spectroscopy ,SPACE groups - Abstract
Uranium dioxide (UO2) is a widely studied material due to its use as fuel in pressurised water reactors (PWR), and Raman spectroscopy is a technique of choice to characterise the evolution of its microstructure. UO2 crystallises in a fluorite CaF2 (space group Fm‐3m) structure that gives rise to a unique Raman signature, the T2g band. However, several other bands are often detected whose attribution remains unclear. The present study gives new insights on the Raman spectrum of UO2 thanks to the combination of isotopic labelling with 18O and Raman imaging. In addition to the expected T2g, U2 (LO), 2LO and U3 bands, we have detected a doublet at 885 and 925 cm−1, a U* band at 555 cm−1 in some specific areas and two bands located at 367 and 1196 cm−1. All Raman bands shift under the effect of the replacement of 16O by 18O, excepting for the U* band that could not be detected anymore. The isotopic shift ratio could be determined for 20% and 30% 18O labelling. No discrepancy in band position is observed between grains and grain boundaries, except for the U2(LO) band. We also evidence a difference between the U defect bands and the 885 and 925 cm−1 doublet bands evolution under labelling, although the latter also seems to be connected to the presence of defects in the material. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
29. Fragmentation and ISRS-Aware Survivable Routing, Band, Modulation, and Spectrum Allocation Algorithm in Multi-Band Elastic Optical Networks.
- Author
-
Liu, Yunxuan, Feng, Nan, Shen, Lingfei, Lv, Jingjing, Yan, Dan, and Zhao, Jijun
- Subjects
SPECTRUM allocation ,RAMAN scattering ,RAMAN effect ,ALGORITHMS ,SIGNAL-to-noise ratio ,BANDWIDTH allocation - Abstract
The C+L band elastic optical networks (C+L-EONs) increase the network capacity significantly. However, the introduction of an L band enhances the inter-channel stimulated Raman scattering effect (ISRS), consequently deteriorating the quality of transmission (QoT) of the signal. Furthermore, spectrum allocation leads to spectrum fragmentation inevitably, which escalates the bandwidth blocking rate. In addition, in C+L-EONs, a single fiber carries more services, and once one of the links fails, a huge number of requests will be interrupted, resulting in huge economic losses. Therefore, this paper proposes a survivability routing, band, modulation, and spectrum allocation (RBMSA) algorithm that effectively guarantees service survivability and reduces the impact of ISRS and spectrum fragmentation. The algorithm employs shared backup path protection and a band partitioning method, whereby the spectrum resource of the primary path is assigned in the L band and the backup path is assigned in the C band in order to minimize the impact of ISRS on the QoT of the request while ensuring the survivability of the network. Furthermore, a fragmentation metric accounting for both the free and shared spectrum resource is proposed to mitigate both free and shared spectrum fragmentation. The simulation results reveal that the proposed RBMSA algorithm reduces the bandwidth blocking probability (BBP) and the fragmentation rate (FR) by 47.7% and 21.3%, respectively, and improves the optical signal-to-noise ratio (OSNR) by 4.17 dB in NSFNET. In COST239, the BBP, FR, and OSNR are 22.1%, 21.5%, and 4.71 dB, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
30. Effects of Raman Labeling Compounds on the Stability and Surface-Enhanced Raman Spectroscopy Performance of Ag Nanoparticle-Embedded Silica Nanoparticles as Tagging Materials.
- Author
-
Yang, Cho-Hee, Cho, Hye-Seong, Kim, Yoon-Hee, Yoo, Kwanghee, Lim, Jaehong, Hahm, Eunil, Rho, Won Yeop, Kim, Young Jun, and Jun, Bong-Hyun
- Subjects
SERS spectroscopy ,SILICA nanoparticles ,RAMAN effect ,OSTWALD ripening ,SUBSTRATES (Materials science) - Abstract
Surface-enhanced Raman spectroscopy (SERS) tagging using silica(SiO
2 )@Ag nanoparticles (NPs) is easy to handle and is being studied in various fields, including SERS imaging and immunoassays. This is primarily due to its structural advantages, characterized by high SERS activity. However, the Ag NPs introduced onto the SiO2 surface may undergo structural transformation owing to the Ostwald ripening phenomenon under various conditions. As a result, the consistency of the SERS signal decreases, reducing their usability as SERS substrates. Until recently, research has been actively conducted to improve the stability of single Ag NPs. However, research on SiO2 @Ag NPs used as a SERS-tagging material is still lacking. In this study, we utilized a Raman labeling compound (RLC) to prevent the structural deformation of SiO2 @Ag NPs under various conditions and proposed excellent SiO2 @Ag@RLC-Pre NPs as a SERS-tagging material. Using various RLCs, we confirmed that 4-mercaptobenzoic acid (4-MBA) is the RLC that maintains the highest stability for 2 months. These results were also observed for the SiO2 @Ag NPs, which were unstable under various pH and temperature conditions. We believe that SERS tags using SiO2 @Ag NPs and 4-MBA can be utilized in various applications on based SERS because of the high stability and consistency of the resulting SERS signal. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
31. 基于拉曼放大的长距离BOTDR传感系统研究.
- Author
-
范 敏, 张明红, 朱 阳打, 赵航航, 郑扬亮, 张礼昌, 石延辉, 李玉华, 袁孝红, and 尹国路
- Subjects
RAMAN effect ,REFLECTOMETRY ,SIGNAL-to-noise ratio ,BRILLOUIN scattering ,SPATIAL resolution - Abstract
Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
32. Broadband noise-like pulses in fiber laser based on a filter.
- Author
-
Meng, Yichang, Ougrige, Oumaima, Bessin, Florent, Salhi, Mohamed, and Sanchez, François
- Subjects
- *
LASER pulses , *TUNABLE lasers , *RAMAN effect , *FIBER lasers , *BANDPASS filters , *ERBIUM - Abstract
We report on the generation of broadband noise-like pulses in an Er:Yb doped fiber laser with a tunable bandpass filter in the cavity. Benefit from the filter enhanced spectrum at shorter wavelengths and Raman effect assisted spectrum at longer wavelengths, an excellent flat spectrum with a 3 dB spectral width of 130.2 nm is obtained. This is different from previous traditional methods to achieve broadband noise-like pulses, and the results also represent the widest spectrum directly obtained in an erbium doped fiber laser without the use of any special fibers within the cavity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Characterization of 2D Transition Metal Dichalcogenides Through Anisotropic Exciton Behaviors.
- Author
-
Chen, Shu‐Hsien, Chang, Sih‐Wei, and Chen, Hsuen‐Li
- Subjects
- *
TRANSITION metals , *RAMAN spectroscopy , *CRYSTAL defects , *ANISOTROPY , *STANDARD deviations , *RAMAN scattering , *RAMAN effect - Abstract
This study reports the first attempt to characterize the quality, defects, and strain of as‐grown monolayer transition metal dichalcogenide (TMDC)‐based 2D materials through exciton anisotropy. A standard ellipsometric parameter (Ψ) to observe anisotropic exciton behavior in monolayer 2D materials is used. According to the strong exciton effect from phonon–electron coupling processes, the change in the exciton in the Van Hove singularity is sensitive to lattice distortions such as defects and strain. In comparison with Raman spectroscopy, the variations in exciton anisotropy in Ψ are more sensitive for detecting slight changes in the quality and strain of monolayer TMDC films. Moreover, the optical power requirement for TMDC characterization through exciton anisotropy in Ψ is ≈10−5 mW cm−2, which is significantly less than that of Raman spectroscopy (≈106 mW cm−2). The standard deviation of the signals varies with strain (defects) in Raman spectra and exciton anisotropies in Ψ are 0.700 (0.795) and 0.033 (0.073), indicating that exciton anisotropy is more sensitive to slight changes in the quality of monolayer TMDC films. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Surface-enhanced Raman effect on MoS2–WS2 composite structures.
- Author
-
Majumdar, Dipanwita
- Subjects
- *
RAMAN effect , *COMPOSITE structures , *CHARGE transfer , *FLUORESCENT dyes , *SURFACE roughness - Abstract
The extensive application of SERS requires a reduction in complexity and difficulty in substrate preparation. Here, the study proposes a simple yet effective technique for the synthesis of few-layered MoS2–WS2 composite structures and highlights the potential of these nano-composites as low-cost SERS substrates. A highly fluorescent dye, Rhodamine 6G (R6G) has been employed as a probe. A better enhancement ability was observed for the MoS2–WS2 nano-composite structures and a series of R6G signature peaks can be detected even down to 10–7 M concentration. The presence of surface roughness due to the formation of multiple inter- and intra-flake heterojunctions may provide a larger contact area between the substrate and the probe. Hence, the improved enhancement is probably due to the higher adsorption of the R6G molecules on the nano-composites and the effective charge transfer between them. Additionally, the detection ability of the MoS2–WS2 composite structures was sustained over a long period after storing the same at room temperature. The study provides a new incentive for metal-free low-cost SERS sensing by engaging 2D materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Fractional Quantum Anomalous Hall Phase for Raman Superarray of Rydberg Atoms.
- Author
-
Poon, Ting Fung Jeffrey, Zhou, Xin‐Chi, Wang, Bao‐Zong, Yang, Tian‐Hua, and Liu, Xiong‐Jun
- Subjects
RYDBERG states ,RAMAN effect ,BOSONS - Abstract
Rydberg atom arrays offer promising platforms for quantum simulation of correlated quantum matter and raise great interests. This work proposes a novel stripe‐lattice model with "Raman superarray of Rydberg atoms" to realize bosonic fractional quantum anomalous Hall (FQAH) phase. Two types of Rydberg states, arranged in a supperarray configuration and with Raman‐assisted dipole‐exchange couplings, are implemented to realize a minimal QAH model for hard‐core bosons populated into a topological flat band with large bulk gap under proper tunable experimental condition. With this the bosonic FQAH phase can be further achieved and probed feasibly. In particular, a novel quench protocol is proposed to probe the fractionalized excitations by measuring the correlated quench dynamics featured by fractional charge tunneling between bulk and chiral edge modes in the open boundary. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
36. Spatiotemporal imaging and manipulation of surface plasmons.
- Author
-
Crampton, Kevin T., Joly, Alan G., Gong, Yu, and El-Khoury, Patrick
- Subjects
SURFACE plasmons ,ULTRASHORT laser pulses ,MATERIALS science ,ELECTRON emission ,RAMAN effect ,ELECTRIC fields ,ULTRA-short pulsed lasers - Abstract
Surface plasmon polaritons (SPPs) are travelling surface waves that have shown promise for applications in nanophotonics as they provide a direct route toward photon-mediated electrical signal generation – a central paradigm for speeding up and scaling down photonic elements. SPP waves have also generated fundamental interest due to their high-field strength and sub-wavelength confinement, properties that have enabled the surface-enhanced Raman effect. Over the last decade, photoemission electron microscopy (PEEM) has emerged as a pioneering technique for imaging surface electric fields through ultrashort laser pulse mediated electron emission and has therefore become an indispensable tool for characterizing plasmonic phenomena at interfaces in a variety of materials. PEEM offers nanometer spatial resolution and femtosecond temporal resolution, allowing SPPs to be prepared, monitored, and manipulated on the nanometer-femtosecond scale. Through a brief review of recent reports, we aim to introduce PEEM-based SPP imaging and manipulation modalities and highlight their utility in the context of emerging nanoscale and quantum materials science advancements. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Nanoimaging in Cancer Part I
- Author
-
Shaikh, Sikandar and Shaikh, Sikandar
- Published
- 2024
- Full Text
- View/download PDF
38. Introduction
- Author
-
Lisyansky, Alexander A., Andrianov, Evgeny S., Vinogradov, Alexey P., Shishkov, Vladislav Yu., Lotsch, H. K. V., Founding Editor, Rhodes, William T., Editor-in-Chief, Adibi, Ali, Series Editor, Asakura, Toshimitsu, Series Editor, Hänsch, Theodor W., Series Editor, Kobayashi, Kazuya, Series Editor, Krausz, Ferenc, Series Editor, Markel, Vadim, Series Editor, Masters, Barry R., Series Editor, Midorikawa, Katsumi, Series Editor, Venghaus, Herbert, Series Editor, Weber, Horst, Series Editor, Weinfurter, Harald, Series Editor, Lisyansky, Alexander A., Andrianov, Evgeny S., Vinogradov, Alexey P., and Shishkov, Vladislav Yu.
- Published
- 2024
- Full Text
- View/download PDF
39. Raman Effect in Non-Raman Lasers
- Author
-
Lisyansky, Alexander A., Andrianov, Evgeny S., Vinogradov, Alexey P., Shishkov, Vladislav Yu., Lotsch, H. K. V., Founding Editor, Rhodes, William T., Editor-in-Chief, Adibi, Ali, Series Editor, Asakura, Toshimitsu, Series Editor, Hänsch, Theodor W., Series Editor, Kobayashi, Kazuya, Series Editor, Krausz, Ferenc, Series Editor, Markel, Vadim, Series Editor, Masters, Barry R., Series Editor, Midorikawa, Katsumi, Series Editor, Venghaus, Herbert, Series Editor, Weber, Horst, Series Editor, Weinfurter, Harald, Series Editor, Lisyansky, Alexander A., Andrianov, Evgeny S., Vinogradov, Alexey P., and Shishkov, Vladislav Yu.
- Published
- 2024
- Full Text
- View/download PDF
40. Design of Raman-Based Sensing Systems
- Author
-
Ratnakar, Tadi Sai, Sadani, Kapil, Nag, Pooja, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Rüdiger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Li, Yong, Series Editor, Liang, Qilian, Series Editor, Martín, Ferran, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Oneto, Luca, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Speidel, Joachim, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zamboni, Walter, Series Editor, Zhang, Junjie James, Series Editor, Tan, Kay Chen, Series Editor, George, V. I., editor, Santhosh, K. V., editor, and Lakshminarayanan, Samavedham, editor
- Published
- 2024
- Full Text
- View/download PDF
41. Discovery of internal rotation and conformers of 1,2-dichloroethane: the dawn of the concept of conformation
- Author
-
Shinji TOYOTA
- Subjects
conformation ,dipole moment ,internal rotation ,molecular structure ,raman effect ,stereochemistry ,Science (General) ,Q1-390 - Abstract
In 1932, Mizushima and Higasi reported the dependence of the dipole moments of 1,2-dichloroethane on both temperature and solvent in the Proceedings of the Imperial Academy, Japan. This report was followed by their first proposal of the existence of conformers that exchanged by internal rotation about a C–C single bond based on experimental data. Their monumental work marked the beginning of the essential concept of conformation in modern stereochemistry. Their proposal was later confirmed by the direct observation of the anti and gauche conformers of 1,2-dichloroethane by Raman spectroscopy, and further supported by other experimental and theoretical methods. The relative stabilities of the anti and gauche conformers of 1,2-dichloroethane and other 1,2-disubstituted ethanes were discussed in terms of steric, electrostatic, and stereoelectronic effects based on analysis of calculated data. Those studies influenced the development of subsequent research in organic chemistry, such as the conformational analysis of cyclohexane derivatives and the isolation of chiral gauche conformers.
- Published
- 2024
- Full Text
- View/download PDF
42. Recent advances in the design of SERS substrates and sensing systems for (bio)sensing applications: Systems from single cell to single molecule detection [version 1; peer review: awaiting peer review]
- Author
-
Sai Ratnakar Tadi, Ashwini G Shenoy, Anirudh Bharadwaj, Sreelakshmi C S, Chiranjay Mukhopadhyay, Kapil Sadani, and Pooja Nag
- Subjects
Review ,Articles ,Raman effect ,Surface Enhanced Raman Spectroscopy ,Disposable substrates ,Point-of-use ,Single-molecule sensing ,Bioreceptor. - Abstract
The Raman effect originates from spontaneous inelastic scattering of photons by matter. These photons provide a characteristic fingerprint of this matter, and are extensively utilized for chemical and biological sensing. The probability of generation, and hence the detection of these Raman scattered photons, is very low; hence, it is difficult to use this directly for sensing in complex matrices. To amplify this signal, surface-enhanced Raman spectroscopy (SERS) has been extensively investigated and has emerged as a powerful analytical tool for sensing diverse analytes, including ions, small molecules, inorganics, organics, radionucleotides, and cells. Plasmonic nanoparticles, called hotspots, exhibit localized surface plasmon resonance (LSPR). This amplifies the Raman signal and may offer up to a 10 10-fold SERS signal enhancement. The development of SERS active substrates requires further consideration and optimization of several critical features such as surface periodicity, hotspot density, mitigation of sample or surface autofluorescence, tuning of surface hydrophilicities, use of specific (bio) recognition elements with suitable linkers and bioconjugation chemistries, and use of appropriate optics to obtain relevant sensing outcomes in terms of sensitivity, cross-sensitivity, limit of detection, signal-to-noise ratio (SNR), stability, shelf-life, and disposability. This article details the optimization of the aforementioned considerations in the use of disposable materials such as commercial grades of paper, textiles, glasses, polymers, and some specific substrates such as blue-ray digital versatile discs (DVDs) for use as SERS-active substrates for point-of-use (POU) sensing applications. The advancements in these technologies have been reviewed and critiqued for analyte detection in resource-limited settings, highlighting the prospects of applications ranging from single-molecule to single-cell detection.
- Published
- 2024
- Full Text
- View/download PDF
43. Mineralogical Characteristics and Magmatic Evolution Significance of Garnets in the Late Jurassic Granites in Xingcheng, Eastern North China Craton.
- Author
-
Shiyao Gao, Xu, Zhongjie, Zhao, Fufeng, Cao, Ke, and Tang, Nanyu
- Subjects
- *
GARNET , *RAMAN effect , *GRANITE , *ELECTRON probe microanalysis , *OROGENIC belts - Abstract
A series of Mesozoic granites related to the subduction of the ancient Pacific plate are widely developed in the eastern part of the North China Craton. These granites contain garnet as a minor phase. Garnet records important information such as magma composition, temperature and pressure, and is an important object in the study of petrological evolution of granites. We take the late Jurassic garnet–bearing monzogranite in Xingcheng, Liaoning as the research object, and the magmatic evolution process in the study area is discussed by the in–situ element geochemical variation and the Raman effect of magmatic garnet girdle. It is found that the garnet has a zonation structure in which the contents of MnO and CaO increase and then decrease, while the contents of FeO and MgO decrease and then increase from the core to the edge. Through the simulation of the crystallization sequence of garnet and biotite, it is found that the garnet has "M" type "spessartine bell–shaped profile", Mn/(Ca + Mg + Fe) value and Mn/Fe value, which reflects that the crystallization pattern of minerals in the magma is dominated by biotite crystallization to garnet crystallization. It is considered that forward and reverse girdle can exist in the same garnet; the separation and crystallization of minerals in the late magmatic evolution is the main reason for the change in the compositional profile of the garnet. This is consistent with the late evolution of granitic magmas in the northeastern of the North China Craton after the late Jurassic. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
44. Raman Spectroscopy as a Research and Diagnostic Tool in Clinical Hematology and Hematooncology.
- Author
-
Laskowska, Paulina, Mrowka, Piotr, and Glodkowska-Mrowka, Eliza
- Subjects
- *
BLOOD diseases , *MOLECULAR spectroscopy , *RAMAN effect , *MOLECULAR interactions , *CHEMICAL structure , *RAMAN spectroscopy - Abstract
Raman spectroscopy is a molecular spectroscopic technique able to provide detailed information about the chemical structure, phase, crystallinity, and molecular interactions of virtually any analyzed sample. Although its medical applications have been studied for several decades, only recent advances in microscopy, lasers, detectors, and better understanding of the principles of the Raman effect have successfully expanded its applicability to clinical settings. The promise of a rapid, label-free diagnostic method able to evaluate the metabolic status of a cell in vivo makes Raman spectroscopy particularly attractive for hematology and oncology. Here, we review widely studied hematological applications of Raman spectroscopy such as leukocyte activation status, evaluation of treatment response, and differentiation between cancer and non-malignant cells, as well as its use in still unexplored areas in hematology. We also discuss limitations and challenges faced by Raman spectroscopy-based diagnostics as well as recent advances and modifications of the method aimed to increase its applicability to clinical hematooncology. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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45. Bioinorganic Materials for Imaging, Diagnosis and Therapy of Neurological Disease.
- Author
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Zhao, Yangyang, Ngai, Howai, Wang, Fan, Liu, Yawei, Sun, Yao, Zhang, Hongjie, Wang, Shidong, Chen, Liang, and Liu, Kai
- Subjects
- *
SURFACE enhanced Raman effect , *NEUROLOGICAL disorders , *RAMAN scattering , *SERS spectroscopy , *ARTIFICIAL intelligence , *NEURAL stimulation , *STEM cell transplantation , *RAMAN effect - Abstract
The treatment of neurological disease, such as epilepsy is rather complicated. Emerging therapies such as surgery, gene therapy, stem cell transplantation, and neurostimulation have been developed to replace traditional drug therapy. However, great challenges such as the difficult localization of epileptic foci (EF), incomplete excision of lesioned nerves, high drug resistance, and severe side effects limit their clinical applications. As an alternative, bioinorganic materials have been emerged and show great potentials for epilepsy theranostics. Their unique physical properties, including fluorescence, magnetic resonance effect, and surface‐enhanced Raman scattering effect (SERS), give them the ability to image the localization of EF. In addition, the fluorescence and conductivity of bioinorganic materials could be further used for studying pathogenesis. Moreover, bioinorganic materials could serve as intelligent systems to deliver drugs and cooperative therapy for epilepsy. Herein, this review highlights the design and application of bioinorganic materials in the imaging, diagnosis, and therapy of epilepsy. Furthermore, light is shown on the potential bottlenecks and future perspectives of bioinorganic materials in epilepsy theranostics. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
46. Investigation of graphene flake and photonic crystal structure enhancement effect by Raman spectroscopy of thymine.
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Yaremkevych, A., Fesenko, O., Hryn, V., Yezhov, P., Bellucci, S., and Smirnova, T.
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RAMAN effect , *PHOTONIC crystals , *THYMINE , *CRYSTAL structure , *BIOMOLECULES , *SERS spectroscopy , *RAMAN spectroscopy - Abstract
Raman spectroscopy is widely used for studying bioorganic materials. However, dealing with biological samples presents challenges such as limited quantities, tight timelines, complex preparation, and the need for improved precision. Hence, efforts are needed to enhance sensitivity and visualization for specific molecules or cells. This study explored using periodic waveguide structures (PWS) to amplify Raman signals of biological molecules, focusing on thymine. We found that composite nanostructures significantly boosted thymine's Raman signal, further enhanced by injecting graphene nanoflakes. This research highlights the potential of enhanced Raman techniques in bioanalysis and paves the way for future advancements in this field. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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47. In‐Source High‐Resolution Spectroscopy Using an Integrated Tunable Raman Laser.
- Author
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Granados, Eduardo, Stoikos, Georgios, Bernerd, Cyril, Chrysalidis, Katerina, Echarri, Daniel T., Fedosseev, Valentin N., Heinke, Reinhard, and Marsh, Bruce A.
- Subjects
- *
TUNABLE lasers , *ATOMIC physics , *NUCLEAR physics , *RAMAN effect , *SPECTROMETRY , *RAMAN lasers - Abstract
Tunable single‐frequency lasers are the most prominent tool for high‐resolution spectroscopy, allowing for the study and exploitation of the electronic structure of atoms. A significant milestone relies on the demonstration of integrated laser technology for performing such a task. The device presented here is composed of a compact Fabry–Perot monolithic resonator capable of producing tunable and Fourier‐limited nanosecond pulses with a MHz‐class frequency stability without active cavity stabilization elements. It also has the remarkable capability of exploiting the Raman effect to funnel efficiently the broad spectrum of an input laser to a spectrally‐bright Stokes pulse at hard‐to‐access wavelength ranges. The targeted atom for the demonstrations is 152Sm, released as an atomic vapor in a hot cavity environment. Here, the Stokes field is tuned to a wavelength of 433.9 nm, while a crossed‐beams spectroscopy setup is used to minimize the Doppler broadened spectral features of the atoms. With this work, the suitability of integrated diamond Raman lasers as a high‐resolution in‐source spectroscopy tool is demonstrated, enabling many applications in atomic and nuclear physics. The integrated form‐factor and inherent simplicity makes such a laser an interesting prospect for quantum‐technology based sensing systems and related applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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48. Raman enhancement induced by exciton hybridization in molecules and 2D materials.
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Kitadai, Hikari, Tan, Qishuo, Ping, Lu, and Ling, Xi
- Subjects
SERS spectroscopy ,RAMAN effect ,RAMAN spectroscopy ,MOLECULES ,SMALL molecules - Abstract
Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for trace-level fingerprinting. Recently, layered two-dimensional (2D) materials have gained significant interest as SERS substrates for providing stable, uniform, and reproducible Raman enhancement with the potential for trace-level detection. Yet, the development of effective 2D SERS substrates is still hindered by the lack of fundamental understanding of the coupling mechanism between target molecules and substrates. Here, we report a systematic excitation-dependent Raman spectroscopy investigation on the coupling between 2D materials such as SnS
2 , MoS2 , WSe2 , and graphene and small organic molecules like rhodamine 6G (Rh 6G). Strong coupling between SnS2 and Rh 6G is found due to their degenerate excitons through Raman excitation profiles (REP), leading to the enhancement of Rh 6G vibrational modes that are observable down to 10−13 M. Our study shows that exciton coupling in the substrate-adsorbate complex plays a vital role in the Raman enhancement effect, opening a new route for designing SERS substrates for high sensitivity. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
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49. Label‐free surface‐enhanced Raman spectroscopy coupled with machine learning algorithms in pathogenic microbial identification: Current trends, challenges, and perspectives
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Jia‐Wei Tang, Quan Yuan, Xin‐Ru Wen, Muhammad Usman, Alfred Chin Yen Tay, and Liang Wang
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deep learning ,label‐free SERS ,machine learning ,microbial diagnosis ,Raman effect ,spectroscopy ,Medical technology ,R855-855.5 ,Biotechnology ,TP248.13-248.65 - Abstract
Abstract Infectious diseases caused by microbial pathogens remain a primary contributor to global health burdens. Prompt control and effective prevention of these pathogens are critical for public health and medical diagnostics. Conventional microbial detection methods suffer from high complexity, low sensitivity, and poor selectivity. Therefore, developing rapid and reliable methods for microbial pathogen detection has become imperative. Surface‐enhanced Raman Spectroscopy (SERS), as an innovative non‐invasive diagnostic technique, holds significant promise in pathogenic microorganism detection due to its rapid, reliable, and cost‐effective advantages. This review comprehensively outlines the fundamental theories of Raman Spectroscopy (RS) with a focus on label‐free SERS strategy, reporting on the latest advancements of SERS technique in detecting bacteria, viruses, and fungi in clinical settings. Furthermore, we emphasize the application of machine learning algorithms in SERS spectral analysis. Finally, challenges faced by SERS application are probed, and the prospective development is discussed.
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- 2024
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50. G phonon mode splitting in doped bilayer graphene probed by in-situ transport measurement and Raman spectroscopy.
- Author
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Moulick, Shubhadip, Mukherjee, Shubhrasish, Raha, Sreyan, Singha, Achintya, and Pal, Atindra Nath
- Subjects
- *
RAMAN spectroscopy , *GRAPHENE , *PHONONS , *CARRIER density , *ELECTRON-phonon interactions , *RAMAN effect , *DOPING agents (Chemistry) , *CHARGE carrier mobility - Abstract
Two dimensional material like graphene, TMDC's have shown a lot of promises due to their excellent electrical and optical properties. Graphene devices fabricated so far relied on lithographic techniques which always leave an un-intentional residue on the graphene surface. Here, we have created a bilayer graphene device avoiding the conventional lithographic procedure by transferring the graphene layer directly on top of the metal electrodes. We tune the carrier density by the application of an electrolyte top gate, and a high doping level (∼ 1013/cm2) can be accessed due to the formation of a nanometer-thick Debye layer. We performed in-situ Raman spectroscopy by varying the carrier concentration. A prominent blue shift of the characteristic G peak was noticed with increasing carrier concentration, originating possibly due to enhanced electron-phonon interaction. Moreover, we observed a splitting of the G peak at higher doping concentration, may arise due to mixing of symmetric and antisymmetric modes by breaking the layer symmetry of the bilayer graphene. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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