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Ni-doped molybdenum disulfide (MoS 2) powders at 1%, 2%, 3%, 4%, 5% and 7% of Ni are prepared by the hydrothermal method. Sophisticated analytical studies such as X-ray diffraction, Raman, TEM and photoluminescence (PL) were analyzed to predict their structural, morphological and optical properties. Effects of Ni-doping with MoS2 on crystalline structure, morphology as well their optical phenomenon were examined in detail. Ni doping on MoS2 revealed tetragonal crystal structure of the parent compound. A significant decrease in their optical energy gap (from 1.86 to 1.76 eV) was perceived with Ni doping concentration increment. PL intensity exhibited a considerable improvement with Ni-doped MoS2 samples at room temperature. From a theoretical viewpoint, the compact density matrix method is applied for Ni–MoS2 to calculate their linear and nonlinear absorption coefficients as well as refractive index modulations for undoped and Ni-doped samples at the focal points of their corresponding intra-band and inter-band transitions. Observed findings are well correlated with the practical results which prove that Ni–MoS2 layers are promoters for potential applications in optoelectronic technology. [ABSTRACT FROM AUTHOR]

To demonstrate that the Z-scan technique is a reliable approach for diagnosing normal and cancer cells, the absorption coefficient (α), nonlinear refractive index (n2) of normal (MCF10A) and cancer cell lines (MCF7) were examined. According to our findings of the optical properties of cells, cancer cells shown to have higher linear absorption coefficient than normal cells as well as nonlinear refractive index (n2) of different signs but the same order of (10-7 cm2/W). This method is a quick method for differentiating between normal and cancerous breast cells, making it suitable for use in clinical stages in the future. This is because of the obvious fundamental difference between the optical behavior of normal and cancer cells, as well as the affordability, the potential for reproducibility without compromising sample quality, and the high accuracy.

Morphology-rich ZnO as a direct band gap II–VI semiconductor is a promising material for photonic, optical, and electronic devices. Nanostructured materials have provided a leading edge to the next-generation technology due to their distinguished performances and efficiencies for device fabrication. The nonlinear optical (NLO) properties and mechanisms dependent on the size and dimensionality of ZnO nanostructures remain to be elucidated. Herein, we begin to provide a comprehensive summary of the status of research activities in ZnO nanostructures, including their syntheses and potential applications, with an emphasis on multidimensional ZnO nanostructure based growth, properties, and applications. Density functional theory calculations confirmed the effect of ZnO size, morphology, and defect on the structure, work function, and charge density distribution of the electron band. Finite difference time domain simulation confirmed that the electric field, magnetic field, and Poynting vector of the ZnO system with the morphology changes were applied. Moreover, the ultrafast NLO and carrier dynamics of feature-rich ZnO nanostructures were studied. The effects of different experimental parameters on the morphology and linear and nonlinear excitation and radiation mechanisms of ZnO nanostructures were studied by constructing an electron transfer mechanism diagram and the Z-scan technique. The results show that the properties and properties of ZnO nanostructures can be regulated and controlled by the structure and morphology. The application and performance of feature-rich zinc oxide nanostructures in photoelectric functional devices are prospected, which will provide valuable references and guidance for related researchers. [ABSTRACT FROM AUTHOR]

This study examined 42 mushroom samples and corresponding cultivated substrates. The radionuclide activity concentrations and bioconcentration factor (BCF) from substrate-to-mushroom were determined. The substrate activity concentrations were 59.1–727.5, 4.5–37.6, and 4.0–53.0 Bq/kg dw (dry weight) for 40 K, 226Ra, and 232Th, respectively. The average 40 K concentrations were 1546.5, 1115.7, and 749.3 Bq/kg dw; the BCFs were 2.49, 3.56, and 5.58 for A. bisporus, F. velutipes, and L. edodes, respectively. The 40 K concentrations were insignificantly correlated with each species' corresponding substrate concentration. The 40 K BCFs had a significantly negative correlation with the substrate concentration for each species. Each mushroom species' 40 K concentration was almost stable, suggesting that 40 K has a regulated homeostasis for a given species. The average 226Ra concentrations were 5.5, 5.4, and 3.4 Bq/kg dw; the BCFs were 0.58, 0.17, and 0.50 for L. edodes, A. bisporus, and F. velutipes, respectively. The average 232Th concentrations were 4.7, 4.7, and 3.0 Bq/kg dw; the BCFs were 0.50, 0.11, and 0.53 for L. edodes, A. bisporus, and F. velutipes, respectively. The 226Ra and 232Th concentrations in mushrooms had a weak to moderate correlation with the cultivated substrate concentrations. The absorption of the 226Ra and 232Th from substrate-to-mushroom was similar to the hypothesis of the linear model that mushroom concentration yields a positive correlation with substrate concentration. [ABSTRACT FROM AUTHOR]

The thermal lens effect is analyzed as a time-resolved Z-scan measurement using cw-single Gaussian beam configuration. The main characteristics of the measurement method are determined. We focus on the evaluation of the measurement error from statistical calculations to also check the linearity of the response and the way to extract the thermo-optical characteristics of absorbing liquids. The results are also applied to demonstrate the feasibility of absorption and scattering efficiencies determination on gold nanoparticles of 5 and 50 nm diameters. [ABSTRACT FROM AUTHOR]

With the help of the developing concrete technology, light concrete and fly ash may be used in several concrete-related fields. To provide protection from radiation, which is one of the current problems of the world, several researchers have used fly ash, but very few researchers have worked on light concrete. To be protected from the effects of radiation, researchers have examined gamma radiation absorption properties by using heavy concrete and heavy aggregates. In this study, by using Class C fly ash at the doses of 30–50–100% instead of cement, three different light concretes were prepared. Density and compressive strength experiments were conducted on the composite blocks prepared with dimensions of 50*50*50 mm, and linear absorption coefficients (cm−1), mass attenuation coefficients (MAC) and Tenth value layer (TVL) radiation interaction parameters were measured. Radiation interaction parameters were obtained using an HP Ge gamma detector. For radiation measurements, four different photon energies as 583 keV (133Ba), 609 keV (133Ba), 661 keV (137Cs) and 911 keV (133Ba) were used. As a result of the analyses, it was determined that compressive strength decreased as the fly ash content increased, the lowest compressive strength values were obtained in the samples containing 100% fly ash among the prepared composites, and density increased as the fly ash content decreased. It was observed that, in the prepared composites, as the energy levels increased, the linear absorption coefficients also increased, and the samples containing 30% fly ash provided the best TVL value on the energy level of 911 keV. With this study, it was revealed that fly ashes that are used in many fields could be used as a radiation shield. Additionally, with this study, due to not using heavy aggregates and due to the production of light concrete in the production of radiation shields, the cost of shield production will significantly decrease. [ABSTRACT FROM AUTHOR]

An analysis of the self-focusing of Hermite Gaussian chirped pulse laser in the relativistic and ponderomotive regime under the influence of exponential plasma density ramp and linear absorption has been done. Differential equation for beam width parameter is derived by using paraxial ray approximation and then solved numerically. It is observed that self-focusing of the chirped pulse laser is strongly influenced by linear absorption. Also it is seen that with the increase in intensity of laser beam, plasma density ramp and chirped parameter value, self-focusing becomes more effective. Current work may be useful in understanding laser induced fusion, quantum dots etc. [ABSTRACT FROM AUTHOR]

Frequency down-conversion (difference frequency generation) of a multiline Q-switched CO laser with a ZnGeP2 crystal was numerically studied. Two options of the CO laser spectrum were considered: "narrow" (44 lines) and "broad" (150 lines) ones. An influence of the ZnGeP2 crystal absorption on THz generation was taken into account and was shown to be significant. It affected optimal phase-matching angle, THz spectrum and frequency conversion efficiency, which were optimized by the crystal length. Maximal frequency conversion efficiency of 0.007% was numerically obtained for the "narrow" spectrum due to less influence of the crystal absorption. [ABSTRACT FROM AUTHOR]

Two new dimeric copper (II) complexes containing 2-chlorobenzoato/4-formylbenzoato and 4-cyanopyridine ligands, [Cu2(μ2-O2CC6H4-Cl)4(C5H4N-CN)2] (1) and [Cu2(μ2-O2CC6H4-CHO)4(C5H4N-CN)4] (2), were synthesized and characterized by elemental analysis, FT-IR and ESR spectroscopy and single-crystal X-ray diffraction methods. In the structure of 1, each copperII cation was surrounded by four oxygen atoms from four different carboxylate of four 2-chlorobenzoate molecules and one nitrogen atom of one 4-cyanopyridine ligand. In the crystal structure of 2, each copperII cation was coordinated by four oxygen atoms from one chelating and two bridging 4-formylbenzoate anions and two nitrogen atoms of two 4-cyanopyridine ligands. C–H···O and C–H···Cl hydrogen bonds (for 1) and C–H···O hydrogen bonds and weak C–H···π interactions (for 2) further stabilize the crystal structures. The linear optical absorption characterizations of the complexes were performed by using UV-Vis spectrophotometer. The results obtained from the linear absorption spectra of the complexes observed that these complexes can be used for optical filtration among nearly 600 and 950 nm wavelengths for concentrations which are higher than 4 g/L. Synopsis: Two new dimeric copper (II) complexes were synthesized. The complexes were characterized by elemental analysis, FT-IR and ESR spectroscopy and single-crystal X-ray diffraction methods. [Cu2(μ2-O2CC6H4-Cl)4(C5H4N-CN)2] (1) has a paddle-wheel structure unit. [Cu2(μ2-O2CC6H4-CHO)4(C5H4N-CN)4] (2) has an unusual and unique conformation. The linear optical absorption characterizations of the complexes were investigated. According to the results obtained from the linear absorption spectra of the complexes, these complexes can be used for optical filtration among nearly 600 and 950 nm wavelengths for concentrations which are higher than 4 g/L. [ABSTRACT FROM AUTHOR]

Two new complexes, [Co(3-fba)2(na)2(H2O)2] (1) and [Ni(3-fba)2(na)2(H2O)2] (2) (where 3-fba = 3-fluorobenzoate and na = pyridine-3-carboxamide, nicotinamide), were synthesized and characterized using different techniques (elemental analysis, FT-IR, UV-Vis spectrophotometer, single-crystal X-ray diffraction, fluorescence spectroscopy, and TGA/DTA analysis). X-ray structural analysis revealed that 1 and 2 are isostructural and exhibit distorted octahedral coordination geometry. In each molecule, metal atoms (Co+2 and Ni+2) are linked by two 3-fluorobenzoate anions, two pyridine-3-carboxamide ligands, and two water molecules per formula unit. The 3-fluorobenzoate and pyridine-3-carboxamide are monodentate through a carboxylate oxygen atom and the nitrogen atom of the pyridine ring, respectively. UV-Vis results showed that the studied complexes have absorption edges similar to semiconductor structures. Namely, 1 and 2 indicated emission behaviors around 370 nm and 361 nm, respectively. [ABSTRACT FROM AUTHOR]

By studying the linear and nonlinear properties of four-level quantum system near plasmonic nanostructure (PS), it is realized that the diffraction efficiency of weak probe light can be controlled by plasmon induced linear and nonlinear modulation. We investigated that due to presence of plasmonic nanostructure, the giant Kerr nonlinearity with vanishing linear and nonlinear absorption can be obtained. In this case, a weak probe light can be diffracted to the higher-order direction due to modulation of nonlinear susceptibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • Improved experimental protocol combining Z-scan thermal lens measurements with circular top-hat beams. • Extension of the standard experimental procedure to higher absorbances. • Measurements of the photothermal efficiency of gold spherical nanoparticles of 5 , 40 , 60 and 80 n m diameters at blue, green and red wavelengths. • Good agreement between the experimentally measured photothermal efficiencies and those calculated with Mie theory. Using continuous-wave (cw) single-beam Z-scan technique, the absorption and scattering efficiencies of spherical gold nanoparticles (NPs) of varying diameter are determined experimentally through the thermal lens (TL) effect for three different wavelengths in the blue, the green and the red. The main characteristics of the measurement method are detailed, extending the usual experimental procedure for weak absorption with Gaussian beams to higher absorption with top-hat beams. To confirm the validity of our approach, the experimental TL data were compared to the theoretical values from Mie theory and found to be in good agreement within the experimental errors. As expected, the photothermal efficiency of spherical gold NPs increases with lower diameters and towards shorter wavelengths. [ABSTRACT FROM AUTHOR]

Noncritical phase-matched (NCPM) fourth harmonic generation (FHG) of 1053 nm was conducted at different regions of a traditional grown large-size 65.8% deuterated potassium dihydrogen phosphate (DKDP) crystal. NCPM FHG was realized at the temperature of 32.1–32.4 °C. The 0.3 °C variation of the temperature is induced by the 0.12% inhomogeneity of deuterium content. Comparing with 2.3 °C of temperature acceptance, the 0.3 °C variation is acceptable. Thus, the traditional grown DKDP crystal is in good homogeneity of deuterium content in view of NCPM FHG. On the other hand, the linear absorption coefficient varies from 0.08 cm −1 to 0.12 cm −1 . When driven with 0.85 GW/cm 2 of second harmonic radiation, the FHG conversion efficiency reaches 68.9%. Larger linear absorption leads to 3% reduction of the conversion efficiency. Therefore, measures should be taken to suppress the linear absorption. [ABSTRACT FROM AUTHOR]

Abstract In this work, total (linear and nonlinear) optical absorption from InTl 1−x Sb x QD structures was studied. It is shown that these Tl-based QD structures have high absorption at long wavelengths. Nonlinear absorption at high power levels was preferred at some slow-light applications. The structures studied assess the possibility of infrared applications of Tl-based structures. [ABSTRACT FROM AUTHOR]

The exact solutions for the viscous fluid through a porous slit with linear ab-sorption are obtained. The Stokes equation with non-homogeneous boundary conditions is solved to get the expressions for the velocity components, pressure distribution, wall shear stress, fractional absorption, and leakage flux. The volume flow rate and mean flow rate are found to be useful in obtaining a convenient form of the longitudinal velocity component and pressure difference. The points of the maximum velocity components for a fixed axial distance are identified. The value of the linear absorption parameter is ran-domly chosen, and the rest available data of the rat kidney to the tabulate pressure drop and fractional absorption are incorporated. The effects of the linear absorption, uniform absorption, and flow rate parameters on the flow properties are discussed by graphs. It is found that forward flow occurs only if the volume flux per unit width is greater than the absorption velocity throughout the length of the slit, otherwise back flow may occur. The leakage flux increases with the increase in the linear absorption parameter. Streamlines are drawn to help the analysis of the flow behaviors during the absorption of the fluid flow through the renal tubule and purification of blood through an artificial kidney. [ABSTRACT FROM AUTHOR]

In this paper, we report on the theoretical simulation and experimental investigation on a novel ultraviolet (UV) laser at 281 nm by second-harmonic generation (SHG) of a frequency-doubled nanosecond Nd:YAG laser in CsB3O5 (CBO) crystal. We firstly presented a numerical model that describes the nanosecond type-I SHG of CBO, accounting for pump depletion, beam divergence, beam spatial walk-off, linear absorption, and phase-mismatch in the Gaussian approximation of both spatial and temporal profiles. In experiment, we demonstrated the high average power UV at 281 nm up to 1.3 W by the cascaded SHG of an 1123-nm Nd:YAG laser to 561.5 nm in LBO at first SHG stage and then frequency-doubled again to 281 nm in CBO at second SHG stage. Moreover, we investigated the SHG efficiency and the UV 281-nm laser beam quality theoretically under the experimental conditions, and the calculations agreed well with the experimental results. [ABSTRACT FROM AUTHOR]

Highlights: [•] Two novel dinuclear Cu(I) and Ag(I) complexes were designed, synthesized. [•] The molecular geometry optimization is based on crystal data. [•] The complexes display significantly enhanced two-photon absorption. [•] The Ag(I) complex possesses a large χ (3) in near IR region. [Copyright &y& Elsevier]

Abstract: A series of mono-, di- and hexa-branched pyrimidine derivatives possessing two-photon absorption have been synthesized. The spectral features of the dyes showed solvatochromic with significant bathochromic shifting of the emission spectra and large Stokes shifts in more polar solvents mainly due to the intramolecular charge-transfer. The two-photon absorption cross-section values were measured by two-photon excited fluorescence and open aperture Z-scan methods. The results revealed that the two-photon absorption cross-section values were enhanced with increasing electron-donating strength of the end group and branch number. The photophysical properties of the dyes were further investigated with the aid of theoretical calculations. In addition, the di-branched dyes has the largest values of two-photon absorption cross-section per molecular weight, low cytotoxicity and can be internalized by human liver cancer cell line and accumulates in the cytoplasm, allowing for live cell two-photon fluorescence imaging, so it is promising for in vitro and vivo cellular imaging applications. [Copyright &y& Elsevier]

We report a new regime of filamentation in water in tight focusing geometry, very similar to the so-called superfilamentation seen in air. In this regime there is no observable conical emission and multiple small-scale filaments, but instead a single continuous plasma channel is formed. To achieve this specific regime the principal requirement is the usage of tight focusing and supercritical power of laser radiation. Together they guarantee extremely high intensity in the microvolume in water (∼10 ^14 W cm ^−2 ) and clamp the energy in the ultra-thin (approximately several microns) channel with a uniform plasma density distribution in it. Each point of the ‘superfilament’ becomes a center of spherical shock wave generation. The overlapped shock waves transform into one cylindrical shock wave. At low energies, a single spherical shock wave is generated from the laser beam waist, and its radius tends toward saturation as energy increases. At higher energies, a long stable contrast cylindrical shock wave is generated, whose length increases logarithmically with laser pulse energy. The linear absorption decreases the incoming energy delivered to the focal spot, which dramatically complicates the filament formation, especially in the case of loose focusing. Aberrations added to the optical scheme lead to multiple dotted plasma sources for shock wave formation, spaced along the axis of pulse propagation. Increasing the laser energy launches the filaments at each of the dots, whose overlapping leads to enhancing the length of the whole filament and therefore the shock impact on the material.

Abstract: Two novel bent-shaped D–π–A–π–D chromophore molecules, 2-pyrazolyl-4,6-bis (4-N,N-ethylaminostyryl)pyrimidine (Z1) and 2-imidazolyl-4,6 –bis- (4-N,N- ethylaminostyryl) pyrimidine (Z2), were synthesized and fully characterized. It was found that the both bent-shaped chromophore molecules crystallize in the orthorhombic system, space group of P212121. The photophysical properties and the connections between structure and properties of the chromophores were investigated both experimentally and theoretically. It was revealed that both absorption and single-photon excited fluorescence (SPEF) spectra show remarkable bathochromic shifts with increasing polarity of the solvents. The two chromophores have strong two-photon excited fluorescence and large two-photon absorption cross-sections in the near-infrared range. Additionally, two-photon microscopy (TPM) fluorescent imaging of BEL-7402 cells labeled with the Z1 and Z2 revealed their potential application as a biological fluorescent probe. [Copyright &y& Elsevier]

Abstract: Four novel dyes are prepared by thiophene as π bridge between carbazole central core and other terminal groups by Suzuki and Heck coupling reactions. These dyes are fully characterized by IR, 1H NMR, 13C NMR, MS and elemental analysis. Linear absorption, single- and two-photon excited fluorescence in various solvents are experimentally investigated. The calculated two-photon absorption cross sections of 9-Hexyl-3,6-di((5-phenyl)-2-thienyl)carbazole (1), 9-Hexyl-3,6-di((5-thienyl)-2-thienyl)carbazole (2), 9-Hexyl-3,6-di((5-p-vinylpyridyl)-2-thienyl)-carbazole (3) and 9-Hexyl-3,6-di-((5-o-vinylpyridyl)-2-thienyl)carbazole (4) for the lowest excited state are 537.84, 550.76, 1292.95 and 1340.40 × 10−50 cm4 s photon−1, respectively. Calculated and experimental data have shown that thiophene as π electron bridge improves the two-photon absorption cross sections greatly. Two-photon optical data recording experiments have been carried out at 820 nm laser radiation. [Copyright &y& Elsevier]

Abstract: A new donor–bridge–acceptor (D–π–A) type ligand (L: 4′-(4-[4-(imidazole)styryl]phenyl)-2,2′:6′,2″-terpyridine) with two-photon absorption and coordination ability was designed and synthesized. Self-assembly of the ligand with HgX2 (X = Cl, Br, I) yielded a series of new coordination complexes (Dyes 1–3) with five-coordinated mercury (ΙΙ), which were characterized by single crystal X-ray diffraction determination. Solvent molecules and various weak interactions, including hydrogen bonds (C–H···N, C–H···X) and π–π interactions played significant roles in the final topological structures. Linear and nonlinear optical properties of the ligand and three dyes were described. Experimental results revealed that two-photon absorption cross sections of three dyes are extraordinary stronger than that of ligand. [Copyright &y& Elsevier]

Abstract: In this paper, we investigated the temperature dependence and optical contrast variations of a nonlinear optical material. The experiments were performed using the close and open aperture z-scan technique using a CW laser beam at 632.8 nm. The nonlinear optical behavior is attributed to thermo-optical effect. The absorption variation as function of temperature is studied. The linear absorption variation induces changes in nonlinear refraction. The nonlinear optical properties of the samples reduce when the temperature increases. [Copyright &y& Elsevier]

Abstract: The linear absorption spectra of the crystals of anthracene, tetracene, and pentacene have been calculated in the case of coupling between Frenkel excitons (FEs), charge transfer excitons (CTEs) and intramolecular vibrations. The model and its parametrization for FEs and CTEs in the plane of those crystals, first developed by Petelenz et al. have been used in the numerical simulations of the linear absorption. The calculated excitonic and vibronic spectra allow us to draw two main conclusions. First, CTEs and their vibronics will manifest themselves in the linear absorption of light polarized along the monoclinic axis only (i.e. for tetracene and pentacene along the crystallographic -axis). Second, the vibronic coupling (FE-phonon and CTE-phonon) emphasizes and increases the number of the maxima due to CTEs manifested in the linear absorption. [Copyright &y& Elsevier]

In a three-level atomic system, the influences of spontaneously generated coherence on the linear absorption and the Kerr nonlinearity are investigated. Our studies show that properties of linear absorption can be dramatically affected by the effect of spontaneously generated coherence. With increase of intensities of spontaneously generated coherence, absorption inhibition will occur, and finally the atomic medium becomes transparent. Furthermore, we find that the Kerr nonlinearity can be obviously enhanced under the action of effects of spontaneously generated coherence. Comparing with traditional scheme of the electromagnetically induced transparency, absorption and Kerr nonlinearity can be controlled without need another driving field in our scheme. [ABSTRACT FROM AUTHOR]

Abstract: We consider a linear stack of periodically arranged donor and acceptor molecules. Such a stack can carry Frenkel excitons (FEs) and charge-transfer excitons (CTEs). We study the case that the FE, excited at the donor, and the CTE, the hole of which is localized at the donor with the electron sitting at one of the neighboring acceptors, are transported through the stack, and that they interact among each other and with local vibrations at the donor and the acceptor. For this system we calculate the excitonic and one- as well as two-vibronic lines. [Copyright &y& Elsevier]

Abstract: A theoretical study of an exciton confined in a quantum dot with the Woods–Saxon potential is presented. The great advantage of our methodology is that it enables confinement regimes by varying two parameters in the model potential. Calculations are made by using the method of the numerical diagonalization of the Hamiltonian matrix within the effective-mass approximation. The binding energies of the ground () and first excited () states are obtained as functions of the dot radius. Based on the computed energies and wave functions, the linear, the third-order nonlinear and the total optical absorption coefficients have been examined between the ground and the first excited states. The results are presented as a function of the incident photon energy for the different values of the dot radius and the barrier slope. It is found that the binding energy and the optical properties of the excitons in a quantum dot are strongly affected by the dot radius and the barrier slope of the confinement potential. [Copyright &y& Elsevier]

Abstract: The linear absorption spectra of a molecular stack of alternatingly and regularly arranged donor and acceptor (D, A) molecules have been studied theoretically for the vibronic spectral regions. The vibronic excitations consist of charge-transfer excitons (CTEs) plus one or two quanta of the intramolecular vibrational mode of the D (A) molecule. The model of CTEs on a DA molecular stack considered by Haarer, Philpott and Morawitz is extended by including the linear and quadratic coupling between CTEs and intramolecular vibrations and represents the basis for the theoretical calculations of the linear optical susceptibility and of the absorption coefficient using the methods of Green’s functions and of canonical transformations. The parameters of the CTEs and of the vibrations obtained in the experimental studies of the absorption, reflection and electroreflectance spectra of the anthracene-PMDA crystal have been introduced in the numerical simulations of the absorption coefficients in pure excitonic, in one- and in two-phonon vibronic spectra. In the case of a relatively weak transfer of the components of the CTEs (of electrons between acceptors and holes between donors) the vibronic spectra will manifest the bound (one-particle) exciton–phonon states only. In the case of stronger transfer, the vibronic absorption spectra will be modified by the impact of many-particle (unbound) exciton–phonon states and the absorption curve will be asymmetrical and broadened (non-Lorentzian). The calculated derivative of the absorption coefficient gives information on vibronic states in both cases of weak and strong transfer. [Copyright &y& Elsevier]

Effects of the film index of nonlinear-cladding optical waveguides on the evolution of fields at medium power levels are investigated numerically. The analysis method is based on mode matching of local normal modes of bounded waveguides. For waveguides with a film whose refractive index is greater than or nearly equal to the linear part of the index of the nonlinear cladding, the path of a beam winds between the film and the nonlinear cladding or in the film. In the case of a film index that is to some extent less than the linear part index of the nonlinear cladding, a beam is emitted to the nonlinear cladding, i.e., spatial soliton emission occurs. The lateral shift of a butt-coupled linear waveguide toward the substrate makes a beam emit to the nonlinear cladding with increased angles. Saturation and linear absorption weakens the winding of a path or decreases the angle of emission. [ABSTRACT FROM PUBLISHER]

In this work, C20, C30 and C40 classification types of concrete where normal aggregate and barite were used as an aggregate have been produce in three different series. The physical properties, mechanical properties and radiation absorption coefficients of these produced concrete have been obtained. The variation of constituent of concrete and the rate of barite in aggregate as a function of strength and linear attenuation coefficients have been obtained by statistical analysis. It has been found that using barite instead of normal aggregate increased linear absorption coefficients and changed the physical and mechanical properties of concrete. [ABSTRACT FROM AUTHOR]

Abstract: The linear absorption spectra in the excitonic and vibronic regions in the case of mixing of Frenkel excitons (FEs) and charge-transfer excitons (CTEs) have been theoretically studied for the exciton parameters of the crystals of MePTCDI and PTCDA. Two coupling parameters for the exciton–phonon coupling are introduced: the FE–phonon coupling and the CTE–phonon coupling. The main features of the vibronics in the absorption spectra are the following: (a) the existence of a doublet structure in the vibronic spectra of CTEs; (b) the vibronic levels of the FE at intermediate values of both coupling parameters are located in the continuum of the many-particle exciton–phonon states which makes its absorption line wide and flat; (c) in the case of strong coupling (coupling constants larger than 1) a doublet of bound states appears above this continuum; (d) in the case of vanishing CTE–phonon coupling the vibronics of the charge transfer excitons practically disappear in the absorption spectra. [Copyright &y& Elsevier]

The commonly used shrinking core model (SCM) envisages a sorbing species to diffuse through a particle as a sharp inward-moving front separating a completely untouched core ahead of the front from a completely saturated shell behind the front. However, in many situations involving the uptake of water soluble species onto sorbent particles and ion exchange resins, the assumption of a completely saturated shell may not be justified. The objective of this communication is to derive a model that generalizes the SCM to allow for an incompletely saturated shell. As with the SCM, the advance of the sorbate into the particle is marked by a distinct interface moving inward with a velocity dictated by the interplay between the rates of diffusion and uptake onto the solid matrix. Local equilibrium is considered to exist between the diffusing sorbing species in the pore space and the form bound to the matrix, as with many homogeneous models such as the linear absorption model (LAM). The model is general enough to accommodate any function describing this local equilibrium. We show that this model simplifies to the conventional SCM as a special limiting case. As an example, the model is applied to previously reported data for the uptake of Cu2+ ions onto calcium alginate gel beads and shown to fit well, comparable to that obtained previously using the SCM and LAM. However, the predicted concentration profiles within a particle during sorption are shown to vary markedly depending on the model. [Copyright &y& Elsevier]

• Surface morphology greatly affects ultrashort pulse laser processing of sapphire. • Total internal reflection (TIR) at rough exit surface enhanced nonlinear absorption. • TIR at rough exit surface resulted in concurrent scribing on entry and exit surfaces. For ultrashort pulse laser processing of a sapphire wafer, nonlinear absorption of laser energy at sufficiently high laser intensity is essential. This study found that in ultrashort pulse laser processing of a sapphire wafer, its surface morphology can have a significant effect on nonlinear absorption and its threshold. Interestingly, for a single side polished wafer, the orientation of the rough or smooth surface towards or away from the laser source (i.e. if the laser is an incident or exit beam) is a critical parameter on the processing outcomes. The orientation of the grinded rough surface affects the amount of light internally reflected within the material; this has a direct impact on the laser energy absorbed and nonlinear absorption threshold. Indeed, the presence of a grinded rough exit surface increases the possibility of total internal reflection of the laser beam at the exit surface; this traps the laser's energy within the material more efficiently and thus promoting nonlinear absorption. This unique characteristic of having total internal reflection at the rough exit surface can result in laser scribing at both the smooth entry and rough exit surfaces simultaneously. This mechanism can be exploited to improve the laser processing of sapphire sample. [ABSTRACT FROM AUTHOR]

The beam waist relative variation (BWRV) method known as a Z-scan based technique is used to demonstrate its feasibility in characterizing the thermal effects induced by a continuous laser beam in different materials. A study of several classical solvent-based solutions (water, ethanol, methanol ...) is carried out before introducing the extension of the BWRV method to laterally map the tested sample. We show that the transverse xy-scan of the sample allows to extract an image of the phase shift due to local thermal heating. This new device, called XYZ-scan, is designed for the thermal characterization of inhomogeneous samples. An example will be given on an inhomogeneous 1.6 μ m thick thin film doped with silver nanoparticles. [ABSTRACT FROM AUTHOR]

• Three novel cadmium (II) complexes were synthesized. • The complexes were characterized by different methods. • Optical absorption and photoluminescent properties of complexes were investigated. • Complex 1 has got very good emission intensity compared to the literature. Three new cadmium–3-fluorobenzoate complexes with pyridine-3-carboxamide/pyridine-3-carboxylate complexes, namely, [Cd 2 (C 7 H 4 FO 2) 4 (C 6 H 6 N 2 O) 2 (H 2 O) 2 (1), [Cd 2 (C 7 H 4 FO 2) 4 (C 6 H 6 N 2 O) 2 (H 2 O) 2 (2), [Cd(C 7 H 4 FO 2)(C 6 H 4 NO 2)(H 2 O)] (3) were obtained under classical and two different hydrothermal conditions, respectively. The structures of all prepared complexes were characterized by elemental analysis, FT-IR and 1H NMR spectroscopy, TGA/DTA and single crystal X-ray analyses. In addition, the structural features of the complexes were studied theoretically by Hirshfeld surface analysis and the X-ray diffraction analyses were supported. It was determined that the carboxylate groups of 3-fluorobenzoate and pyridine-3-carboxylate behaved as chelating bidentate ligands. Hirshfeld surface analysis indicated that H⋯H, H⋯O/O⋯H, H⋯C/C⋯H, H⋯F/F⋯H and C⋯C interactions are the significant contributors to the crystal packing of the synthesized complexes. The thermal stabilities of the synthesized complexes have been investigated and the results showed that the complexes display thermal stability about 100 °C and the decomposition product of anhydrous complexes was CdO. The linear absorption and fluorescence (emission) properties of the complexes were investigated by using UV–Vis and Fluorescence spectroscopic techniques, respectively. It was found that the complex 1 which is synthesized by classical method has got very good emission intensity compared to the materials reported in the literature. This makes the complex 1 potential member for image acquisition without lens and filter, security printing, data recording and storage and laser applications, if its solid form can be done. In addition, it was determined that the classical synthesis has superiority according to the hydrothermal synthesis on the structural, optical absorption and fluorescence properties of the complex. [ABSTRACT FROM AUTHOR]