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Background: Toxoplasma gondii is an intracellular protozoan parasite that is widely distributed in humans and warm-blooded animals. T. gondii chronic infections can cause toxoplasmic encephalopathy, adverse pregnancy, and male reproductive disorders. In male reproduction, the main function of the testis is to provide a stable place for spermatogenesis and immunological protection. The disorders affecting testis tissue encompass abnormalities in the germ cell cycle, spermatogenic retardation, or complete cessation of sperm development. However, the mechanisms of interaction between T. gondii and the reproductive system is unclear. The aims were to study the expression levels of genes related to spermatogenesis, following T. gondii infection, in mouse testicular tissue. Methods: RNA-seq sequencing was carried out on mouse testicular tissues from mice infected or uninfected with the T. gondii type II Prugniaud (PRU) strain and validated in combination with real-time quantitative PCR and immunofluorescence assays. Results: The results showed that there were 250 significant differentially expressed genes (DEGs) (P < 0.05, |log2fold change| ≧ 1). Bioinformatics analysis showed that 101 DEGs were annotated to the 1696 gene ontology (GO) term. While there was a higher number of DEGs in the biological process classification as a whole, the GO enrichment revealed a significant presence of DEGs in the cellular component classification. The Arhgap18 and Syne1 genes undergo regulatory changes following T. gondii infection, and both were involved in shaping the cytoskeleton of the blood–testis barrier (BTB). The number of DEGs enriched in the MAPK signaling pathway, the ERK1/2 signaling pathway, and the JNK signaling pathway were significant. The PTGDS gene is located in the Arachidonic acid metabolism pathway, which plays an important role in the formation and maintenance of BTB in the testis. The expression of PTGDS is downregulated subsequent to T. gondii infection, potentially exerting deleterious effects on the integrity of the BTB and the spermatogenic microenvironment within the testes. Conclusions: Overall, our research provides in-depth insights into how chronic T. gondii infection might affect testicular tissue and potentially impact male fertility. These findings offer a new perspective on the impact of T. gondii infection on the male reproductive system. [ABSTRACT FROM AUTHOR]

A coma-free superhigh spectral resolution optical spectrometer was successfully designed and constructed for practical application. The spectrometer consisted of 20 subgratings and a 2D BSI-CMOS array detector. The spectra were 20-fold with the physical size of the photoelectron detection along the diffraction direction and extended by a factor of 20 to achieve a spectral resolution of 0.01 nm per pixel without any moving parts. Ultrahigh dense emission lines of a hollow cathode Fe lamp were measured. Based on the data analysis and discussions, among the highly resolved spectral lines of Fe measured with an improved signal-to-noise ratio in the 170–600 nm spectral region, 2451 lines were identified in accordance with the reported ones in the literature; however, more than 1100 lines with lower intensity remained unassigned with an unknown mechanism of their origins. Our experimental data indicated the need to more fundamentally study and explore the spectral data of the Fe atoms with the potential for broad application prospects for Fe-based materials in the future. [ABSTRACT FROM AUTHOR]

It is of great technological importance in the field of plasmonic color generation to establish and understand the relationship between optical responses and the reflectance of metallic nanoparticles. Previously, a series of indium nanoparticle ensembles were fabricated using electron beam evaporation and inspected using spectroscopic ellipsometry (SE). The multi-oscillator Lorentz–Drude model demonstrated the optical responses of indium nanoparticles with different sizes and size distributions. The reflectance spectra and colorimetry characteristics of indium nanoparticles with unimodal and bimodal size distributions were interpreted based on the SE analysis. The trends of reflectance spectra were explained by the transfer matrix method. The effects of optical constants n and k of indium on the reflectance were demonstrated by mapping the reflectance contour lines on the n-k plane. Using oscillator decomposition, the influence of different electron behaviors in various indium structures on the reflectance spectra was revealed intuitively. The contribution of each oscillator on the colorimetry characteristics, including hue, lightness and saturation, were determined and discussed from the reflectance spectral analysis. [ABSTRACT FROM AUTHOR]

Radiative cooling is a passive cooling strategy that can radiate heat to outer space through the 8 to 13 μm waveband (atmospheric window) and is now widely used for buildings, wearable fabric, solar cells, and electronic devices. Daytime radiative cooling requires both high reflection in the solar spectrum and high absorption/emission in the 8 to 13 μm range. Previous multilayered structures were optimized by changing the thickness ratio of the layers, but the optical properties of multilayer thin films, such as absorptivity, transmissivity, and reflectivity, are determined by complex factors. In this work, several initial multilayer structures were selected and then the thickness of each layer was globally optimized; the theoretically smallest thickness with the best absorption performance was achieved in the 8 to 13 μm range, which significantly improved the cooling performance and reduced costs. We developed an optimized SiO2-Ta2O5 alternating multilayer photonic radiative cooling thin film and fabricated it using ion source assisted electron beam evaporation with an average emissivity of 0.876 within the 8 to 13 μm range and an average reflectivity of 0.963 in the 0.3 to 2.5 μm waveband; it achieved an average temperature reduction of 20.1°C lower than the uncoated substrate and 3.2°C lower than the ambient temperature under direct sunlight with an average solar power of 859.3 W/m2. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Differential transcriptome study on the damage of testicular tissues caused by chronic infection of T. gondii in mice" published in the journal Parasites & Vectors. The correction states that the corresponding authorship and affiliations information of one of the authors, Miao Yu, was incorrect in the original article. The corrected information can be found in this erratum article. The publisher apologizes for any inconvenience caused. Springer Nature, the publisher, remains neutral regarding jurisdictional claims and institutional affiliations. [Extracted from the article]

Unlike the single grating Czerny–Turner configuration spectrometers, a super-high spectral resolution optical spectrometer with zero coma aberration is first experimentally demonstrated by using a compound integrated diffraction grating module consisting of 44 high dispersion sub-gratings and a two-dimensional backside-illuminated charge-coupled device array photodetector. The demonstrated super-high resolution spectrometer gives 0.005 nm (5 pm) spectral resolution in ultra-violet range and 0.01 nm spectral resolution in the visible range, as well as a uniform efficiency of diffraction in a broad 200 nm to 1000 nm wavelength region. Our new zero-off-axis spectrometer configuration has the unique merit that enables it to be used for a wide range of spectral sensing and measurement applications. [ABSTRACT FROM AUTHOR]

Background: Toxoplasma gondii (T. gondii) is an obligate intracellular parasite, which can affect the pregnancy outcomes in infected females by damaging the uterus, and the intrauterine environment as well as and the hypothalamus resulting in hormonal imbalance. However, the molecular mechanisms underlying the parasite-induced poor pregnancy outcomes and the key genes regulating these mechanisms remain unclear. Therefore, this study aimed to analyze the gene expression in the mouse's uterus following experimentally-induced acute infection with T. gondii RH strain. Three groups of female mice were intraperitoneally injected with tachyzoites as follow; 3 days before pregnancy (FBD6), after pregnancy (FAD6), and after implantation (FID8) as the experimental groups. Another corresponding three groups served as control, were injected with normal saline at the same time. Transcriptome analysis of the total RNA extracted from both infected and non-infected mouse uterus samples was performed using RNA sequencing (RNA-Seq). Results: The three experimental groups (FBD6, FAD6, and FID8) had a total of 4,561, 2,345, and 2,997 differentially expressed genes (DEGs) compared to the controls. The significantly upregulated and downregulated DEGs were 2,571 and 1,990 genes in FBD6, 1,042 and 1,303 genes in FAD6 and 1,162 and 1,835 genes in FID8 group, respectively. The analysis of GO annotation, and KEGG pathway showed that DEGs were mainly involved in anatomical structure development, transport, cell differentiation, embryo development, hormone biosynthetic process, signal transduction, immune system process, phagosome, pathways in cancer, and cytokine-cytokine receptor interaction pathways. Conclusion: T. gondii infection can induce global transcriptomic changes in the uterus that may cause pregnancy hypertension, destruct the intrauterine environment, and hinder the normal development of placenta and embryo. Our results may help to understand the molecular mechanisms of the acute T. gondii infection, which could promote the development of new therapeutics or prophylactics for toxoplasmosis in pregnancy. [ABSTRACT FROM AUTHOR]

Background: Some researchers have reported that Toxoplasma gondii can cause serious reproductive impairment in male animals. Specifically, T. gondii destroy the quality of sperm in the epididymis, which affects their sexual ability. However, among such studies, none have investigated the male reproductive transcriptome. Therefore, to investigate the relationship between T. gondii and sperm maturation, we infected mice with T. gondii prugniaud (PRU) strain and performed transcriptome sequencing of the epididymis. Results: Compared with the control group, 431 upregulated and 229 downregulated differentially expressed genes (DEGs) were found (P-value < 0.05, false discovery rate (FDR) < 0.05 and |log2 (fold change)| ≥ 1). According to results of a bioinformatics analysis, Gene Ontology (GO) function is divided into three categories: cellular component, molecular function and biological process. Upon performing GO analysis, we found that some DEGs correlated with an integral part of membrane, protein complex, cell surface, ATP binding, immune system process, signal transduction and metabolic process which are responsible for the epididymal injury. DEGs were mapped to 101 unique KEGG pathways. Pathways such as cytokine-cytokine receptor interaction, glycolysis/gluconeogenesis and apoptosis are closely related to sperm quality. Moreover, Tnfsf10 and spata18 can damage the mitochondria in sperm, which decreases sperm motility and morphology. Conclusions: We sequenced the reproductive system of male mice chronically infected with T. gondii, which provides a new direction for research into male sterility caused by Toxoplasma infection. This work provides valuable information and a comprehensive database for future studies of the interaction between T. gondii infection and the male reproductive system. [ABSTRACT FROM AUTHOR]

Analyzes giant magnetoresistance properties in granular type (Co-Ag)/Ag multilayers with different Co content and sublayer thickness. Information on the deposits of thick single layer Co-Ag granular films and granular type multilayers; Examination of the typical spectrum of low angle-x-ray diffraction and high angle x ray; Information on the dependence of MR value on the bilayer number for Co65Ag35 multilayers.

Deals with a study which examined the magneto-optical and optical properties of ultrathin iron films sandwiched between gold layers. Background on magneto-optical Kerr effect studies on ferromagnetic films; Experimental results and discussions; Conclusion.

MgxZn1−xO (ZMO) thin films with tunable Mg content were deposited by atomic layer deposition (ALD) on silicon substrates at 190 °C. The elemental and structural properties were acquired by X-ray photoelectron spectroscopy, transmission electron microscopy, atomic force microscopy and X-ray diffraction. Spectroscopic ellipsometry measurements were performed to reveal the evolution of the dielectric functions and critical points in the ZMO thin films by point-by-point fit in the photon energy range of 1.2–6.0 eV. The dependence of the dielectric functions on doping content is clearly demonstrated and physically explained. The critical point energies and the types of interband optical transitions were extracted from standard lineshape analysis of the second derivatives of the dielectric functions. The critical point features were discussed in terms of band structure modification and structural homogeneity arisen by introducing the Mg dopant into the films. Controlling these transitions by changing the doping content will be of practical significance in emerging ZMO-based thin-film photonic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Centimeter-scale WS2 ultrathin films were synthesized on sapphire substrates, and they showed highly oriented crystallographic growth along the c axis. Afterwards, the as-grown samples were systematically characterized using various detection methods. Reliable values of the roughness layer thickness and the film thickness were extracted using both atomic force microscopy (AFM) and spectroscopic ellipsometry (SE), and identified using Raman spectroscopy as well. The expansion and tensile strain along the [001] direction were discovered using X-ray diffraction (XRD) measurements. Accurate dielectric functions of WS2 films were derived from the point-by-point fitting results. The critical points (CPs) of WS2, which have not been reported so far, are precisely extracted from the standard critical point (SCP) model. Their origins are uniquely assigned to different interband electronic transitions in the Brillouin zone, including some novel optical structures above 3 eV, which were not investigated in earlier studies. In this work, it is found that dielectric functions are thickness-dependent, while CPs have an opposite nature, and their intrinsic mechanisms are revealed. The as-obtained results can be expected to help people develop more extensive applications of WS2. [ABSTRACT FROM AUTHOR]

Reports that Zn1-xMnxSe thin films were grown by molecular-beam epitaxy (MBE). Characterization of the samples by x-ray diffraction; Measurement of the Faraday rotations of the films.

The tuning of structural, optical, and electrical properties of Al-doped ZnO films deposited by atomic layer deposition technique is reported in this work. With the increasing Al doping level, the evolution from (002) to (100) diffraction peaks indicates the change in growth mode of ZnO films. Spectroscopic ellipsometry has been applied to study the thickness, optical constants, and band gap of AZO films. Due to the increasing carrier concentration after Al doping, a blue shift of band gap and absorption edge can be observed, which can be interpreted by Burstein-Moss effect. The carrier concentration and resistivity are found to vary significantly among different doping concentration, and the optimum value is also discussed. The modulations and improvements of properties are important for Al-doped ZnO films to apply as transparent conductor in various applications. [ABSTRACT FROM AUTHOR]

The band gap and defect features of ultrathin ZrO2 films with varying thicknesses have been investigated by spectroscopic ellipsometry through the point-by-point data inversion method. The ε2-sprectra in the 3–6 eV range are extracted based on an optical model consisting of a Si substrate/effective ZrO2 film/air ambient structure where the effective ZrO2 film is a combination of interfacial layers and ZrO2. Evident widening of the band gap with a reducing size is observed when the effective ZrO2 films are below a critical thickness, somewhere between 8.80 nm and 17.13 nm. This is due to quantum-confinement and amorphous effects. Moreover, the sub-band-gap defects at interfacial layers and in bulk ZrO2 are identified and present strong thickness dependence as well. The interfacial defects at 3.26, 4.13, 4.43, and 4.77 eV mainly exist below the critical thickness and exhibit a significant suppression with increasing film thickness. The bulk defects at 4.15 eV and 4.46 eV dominate in ZrO2 films once they are over the critical thickness. The evolution of the band gap and defects is closely related to variance in the electronic structure of amorphous ZrO2. Our results may be helpful in understanding controversial problems concerning the size effect on ultrathin high-k oxide films and exploring the further miniaturization of electronic devices based on them. [ABSTRACT FROM AUTHOR]

The dielectric functions of direct-current-sputtered wedge-shaped ultrathin titanium (Ti) film on K9 glass were investigated in this paper. The wedge-shaped Ti thin film was deposited under the identical conditions with continuously varied thickness. Atomic force microscope revealed that the thin film surface was very smooth with the surface roughness of about 0.5 nm. The dielectric functions of the wedge-shaped films in the wavelength range of 300-1200 nm were obtained by a focused-beam ellipsometer with the beam size on the sample about 200 μm. Results show that ε, the real part of the dielectric function, is negative almost in the whole spectrum region, proving that the film at the measured area is continuous and shows metallic behavior. On the other hand, ε decreases with the increase in the film thickness, while ε, the imaginary part of the dielectric function, has the opposite variation tendency. The changing of ε with film thickness is due to the reduced electron-electron interactions and enhanced metallic behavior. While for ε, it gets larger with the increase in the film thickness, which is mainly owing to the decrease in the tensile stress in the film. [ABSTRACT FROM AUTHOR]

The BiFeO (BFO) thin film was deposited by pulsed-laser deposition on SrRuO (SRO)-buffered (111) SrTiO (STO) substrate. X-ray diffraction pattern reveals a well-grown epitaxial BFO thin film. Atomic force microscopy study indicates that the BFO film is rather dense with a smooth surface. The ellipsometric spectra of the STO substrate, the SRO buffer layer, and the BFO thin film were measured, respectively, in the photon energy range 1.55 to 5.40 eV. Following the dielectric functions of STO and SRO, the ones of BFO described by the Lorentz model are received by fitting the spectra data to a five-medium optical model consisting of a semi-infinite STO substrate/SRO layer/BFO film/surface roughness/air ambient structure. The thickness and the optical constants of the BFO film are obtained. Then a direct bandgap is calculated at 2.68 eV, which is believed to be influenced by near-bandgap transitions. Compared to BFO films on other substrates, the dependence of the bandgap for the BFO thin film on in-plane compressive strain from epitaxial structure is received. Moreover, the bandgap and the transition revealed by the Lorentz model also provide a ground for the assessment of the bandgap for BFO single crystals. PACS codes:: 78.67.-n, 78.20.-e, 07.60.Fs [ABSTRACT FROM AUTHOR]

The optical properties of Si nanocrystals (nc-Si) with different sizes (2∼5 nm) embedded in a SiO matrix synthesized by the SiO/SiO superlattice approach were studied in a temperature range from room temperature to 600 K by spectroscopic ellipsometry. The Maxwell-Garnett effective medium approximation and Lorentz oscillator model were employed to extract the dielectric function of nc-Si. The results show that the temperature dependence of optical properties of nc-Si is sensitive to its size. An empirical expression of Varshni approximation was obtained to characterize the band-gap energy change of nc-Si at different temperatures. [ABSTRACT FROM AUTHOR]

TiO thin films of different thickness were prepared by the Electron Beam Evaporation (EBE) method on crystal silicon. A variable angle spectroscopic ellipsometer (VASE) was used to determine the optical constants and thickness of the investigated films in the spectral range from 300 to 800 nm at incident angles of 60°, 70°, and 75°, respectively. The whole spectra have been fitted by Forouhi-Bloomer (FB) model, whose best-fit parameters reveal that both electron lifetime and band gap of TiO thin film have positive correlation to the film thickness. The refractive indices of TiO thin film increase monotonically with an increase in film thickness in the investigated spectral range. The refractive index spectra of TiO thin films have maxima at around 320 nm and the maxima exhibit a marginally blue-shift from 327.9 to 310.0 nm with an increase in film thickness. The evolution of structural disorder in the TiO thin film growth can be used to explain these phenomena. [ABSTRACT FROM AUTHOR]

Titanium oxide (TiO2) thin films were prepared by electron-beam evaporation (EBE) method on crystal silicon, and were thermally treated by rapid thermal annealing (RTA) process. X-ray diffraction (XRD) and variable angle spectroscopic ellipsometry (VASE) were used to analyze the crystal structure, band gap, and optical constants evolution of the investigated films. The strongest diffraction peaks in XRD patterns were found to shift to higher 2 θ angle with an increase of film thickness. The lattice spacing decreases and the average grain size increases, indicating the improvement of crystal quality by increasing film thickness. The band gap from well-fitted Forouhi-Bloomer (FB) dispersion model in VASE decreases with an increase of thickness, and one-dimensional quantum confinement effect and disorder effect have been introduced to explain this relation. The refractive indices of TiO2 thin film decrease monotonically with an increase in film thickness in the spectral range from 230 to 800 nm, which can be attributed to the contribution of compressive stress effect. [ABSTRACT FROM AUTHOR]

An effective method for determining the optical constants of TaO thin films deposited on crystal silicon (c-Si) using spectroscopic ellipsometry (SE) measurement with a two-film model (ambient-oxide-interlayer-substrate) was presented. TaO thin films with thickness range of 1-400 nm have been prepared by the electron beam evaporation (EBE) method. We find that the refractive indices of TaO ultrathin films less than 40 nm drop with the decreasing thickness, while the other ones are close to those of bulk TaO. This phenomenon was due to the existence of an interfacial oxide region and the surface roughness of the film, which was confirmed by the measurement of atomic force microscopy (AFM). Optical properties of ultrathin film varying with the thickness are useful for the design and manufacture of nano-scaled thin-film devices. [ABSTRACT FROM AUTHOR]

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Presents a study which determined the manganese composition in zinc[sub1-x]manganese[subx]selenide. Experimental details; Results and discussion; Conclusions.

As the environmental considerations rise all over the world and under the drive of renewable energy policy, the society of hydrogen energy will come out gradually in the future. The proton exchange membrane water electrolyzer (PEMWE) is a very good hydrogen generator, characterized by low cost, high efficiency and zero emission of greenhouse gases. In this study, the micro temperature, humidity, flow, pressure, voltage, and current sensors were successfully integrated on a 50 μm thick Polyimide (PI) substrate by using micro-electro-mechanical systems (MEMS) technology. After the optimal design and process optimization of the flexible 6-in-1 microsensor, it was embedded in the PEMWE for a 500-h persistent effect test and internal real-time microscopic monitoring. [ABSTRACT FROM AUTHOR]

In recent years, various countries have been paying attention to environmental protection issues, believing that climate change is the main challenge to the developed countries' energy policies. The most discussed solution is renewable energy. The energy storage system can reduce the burden of the overall power system of renewable energy. The hydrogen energy is one of the optimal energy storage system options of renewable energy at present. According to these policies and the future trend, this study used micro-electro-mechanical systems (MEMS) technology to integrate micro voltage, current, temperature, humidity, flow and pressure sensors on a 50 μm thick polyimide (PI) substrate. After the optimization design and process optimization, the flexible six-in-one microsensor was embedded in the proton exchange membrane water electrolyzer (PEMWE) for internal real-time microscopic monitoring. [ABSTRACT FROM AUTHOR]

In this work, we present a simple method to improve the thermoelectric performance of the RF sputtered bismuth telluride films by raising the power of deposition. The as-deposited samples synthesized under different powers were investigated and compared. It shows that the films prepared under relatively higher power conditions exhibit much higher electrical conductivity to result in a greater power factor accompanied with a minor drop in the Seebeck coefficients. A relationship is established between the improvement in thermoelectric performance and the decrease in crystallinity, which might also reduce the thermal conductivity. A maximum power factor of 5.65 × 10−4 W·m−1·K−2 at 470 K is obtained for the sample deposited under 50 W with its Seebeck coefficient being −105 μV/K. The temperature-dependent behaviors of the samples are also looked into and discussed. This work might offer an in-situ and cost-effective approach to improve the performance of thermoelectric materials. [ABSTRACT FROM AUTHOR]

We have prepared [Co90Al10/Cu]30 multilayers by ion beam sputtering and studied the behavior of interlayer coupling, magnetoresistance, and the magneto-optical Kerr effect. For Co–Al/Cu multilayers, the in-plane saturation field, coercive force HC and magnetoresistance ratio ΔR/R have been observed to oscillate with a period of about 0.9 nm, as a function of Cu spacer layer thickness. Furthermore, polar Kerr rotation θk in visible wavelength range also oscillates with the same period. The magneto-optical activities may be attributed to changes in the optical constants with the magnetic state. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

In this work, the two-dimensional profile of the light transmission through a prism-like metallic film sample of Au was measured at a wavelength of 632.8 nm in the visible intraband transition region to verify that, beyond the possible mechanisms of overcoming the diffraction limit, a strongly nonuniform optical absorption path length of the light traveling in the metal could induce a lensing effect, thereby narrowing the image of an object. A set of prism-like Au samples with different angles was prepared and experimentally investigated. Due to the nonuniform paths of the light traveling in the Au samples, lens-effect-like phenomena were clearly observed that reduced the imaged size of the beam spot with decreasing light intensity. The experimental measurements presented in the work may provide new insight to better understand the light propagation behavior at a metal/dielectric interface. [ABSTRACT FROM AUTHOR]

Optical spectrometers play a key role in acquiring rich photonic information in both scientific research and a wide variety of applications. In this work, we present a new spectrometer with an ultrahigh resolution of better than 0.012 nm/pixel in the 170–600 nm spectral region using a grating-integrated module that consists of 19 subgratings without any moving parts. By using two-dimensional (2D) backsideilluminated complementary metal-oxide-semiconductor (BSI-CMOS) array detector technology with 2048 × 2048 pixels, a high data acquisition speed of approximately 25 spectra per second is achieved. The physical photon-sensing size of the detector along the one-dimensional wavelength direction is enhanced by a factor of 19 to approximately 428 mm, or 38912 pixels, to satisfy the requirement of seamless connection between two neighboring subspectral regions without any missing wavelengths throughout the entire spectral region. As tested with a mercury lamp, the system has advanced performance capabilities characterized by the highest k parameter reported to date, being approximately 3.58 × 104, where k = (working wavelength region)/(pixel resolution). Data calibration and analysis as well as a method of reducing background noise more efficiently are also discussed. The results presented in this work will stimulate further research on precision spectrometers based on advanced BSI-CMOS array detectors in the future. [ABSTRACT FROM AUTHOR]

Optical spectrometers play an important role in modern scientific research. In this work, we present a two-channel spectrometer with a pixel resolution of better than 0.1 nm/pixel in the wavelength range of 200 to 950 nm and an acquisition speed of approximately 25 spectra per second. The spectrometer reaches a high k factor which characterizes the spectral performance of the spectrometer as k = (working wavelength region)/(pixel resolution) = 7500. Instead of using mechanical moving parts in traditional designs, the spectrometer consists of 8 integrated sub-gratings for diffracting and imaging two sets of 4-folded spectra on the upper and lower parts, respectively, of the focal plane of a two-dimensional backside-illuminated complementary metal-oxide-semiconductor (BSI-CMOS) array detector, which shows a high peak quantum efficiency of approximately 90% at 400 nm. In addition to the advantage of being cost-effective, the compact design of the spectrometer makes it advantageous for applications in which it is desirable to use the same two-dimensional array detector to simultaneously measure multiple spectra under precisely the same working conditions to reduce environmental effects. The performance of the finished spectrometer is tested and confirmed with an Hg-Ar lamp. [ABSTRACT FROM AUTHOR]

The optical properties of aluminum-doped zinc oxide (AZO) thin films were calculated rapidly and accurately by point-by-point analysis from spectroscopic ellipsometry (SE) data. It was demonstrated that there were two different physical mechanisms, i.e., the interfacial effect and crystallinity, for the thickness-dependent permittivity in the visible and infrared regions. In addition, there was a blue shift for the effective plasma frequency of AZO when the thickness increased, and the effective plasma frequency did not exist for AZO ultrathin films (< 25 nm) in the infrared region, which demonstrated that AZO ultrathin films could not be used as a negative index metamaterial. Based on detailed permittivity research, we designed a near-perfect absorber at 2-5 μm by etching AZO-ZnO alternative layers. The alternative layers matched the phase of reflected light, and the void cylinder arrays extended the high absorption range. Moreover, the AZO absorber demonstrated feasibility and applicability on different substrates. [ABSTRACT FROM AUTHOR]

In this work, 4-layered SiO2/Bi2Te3/SiO2/Cu film structures were designed and fabricated and the optical properties investigated in the wavelength region of 250-1200 nm for their promising applications for direct solar-thermal-electric conversion. A typical 4-layered film sample with the structure SiO2 (66.6 nm)/Bi2Te3 (7.0 nm)/SiO2 (67.0 nm)/Cu (>100.0 nm) was deposited on a Si or K9-glass substrate by magnetron sputtering. The experimental results agree well with the simulated ones showing an average optical absorption of 96.5%, except in the shorter wavelength region, 250-500 nm, which demonstrates the superior absorption property of the 4-layered film due to the randomly rough surface of the Cu layer resulting from the higher deposition power. The high reflectance of the film structure in the long wavelength region of 2-20 μm will result in a low thermal emittance, 0.064 at 600 K. The simpler 4-layered structure with the thermoelectric Bi2Te3 used as the absorption layer may provide a straightforward way to obtain solar-thermal-electric conversion more efficiently through future study. [ABSTRACT FROM AUTHOR]

The electron-beam evaporation method was devoted to fabricate anatase-phase TiO2 thin films on silicon substrate. The optical constants of the thin films determined by spectroscopic ellipsometry in the spectral range from 300 to 800 nm were studied in a temperature range from 293 to 533 K. The refractive indices decrease apparently with increasing temperature, and the thermal expansion and electron–phonon interaction can be introduced to elucidate this phenomenon. The absorption edge in extinction coefficient spectra shows a redshift at elevated temperature, which is attributed to thermally driven band gap shrinkage and electron lifetime loss of optical electron transition. [ABSTRACT FROM AUTHOR]

A new type of incidence-angle-variable infrared spectroscopic ellipsometer working in the 2100-10 000 wave number range has been designed and constructed. For the system, the analyzer and polarizer were driven by two microstepping motors having hollow shafts and rotating synchronously with a speed ratio of 2:1, i.e., A=2P. The incidence angle can be varied from 30° to 90° with an accuracy of 0.01°. The doubled Fourier transforms as both functions of the wave number and the azimuthal angles of the polarizer and analyzer were carried out and integrated in the system. Two sets of ellipsometric parameters measured in the experiment have been used to test the data self-consistency of the system. In data reduction, the error arising from the slight anisotropy of the stray light was corrected. In application, the complex dielectric function of the Au film was measured with a data accuracy better that 1% in the entire spectral range. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]