Search

This work determines a new set of EUV/x-ray optical constants for aluminum (Al), one of the most important materials in science and technology. Absolute photoabsorption (transmittance) measurements in the 17–1300 eV spectral range were performed on freestanding Al films protected by carbon (C) layers, to prevent oxidation. The dispersive portion of the refractive index was obtained via the Kramers–Kronig transformation. Our data provide significant improvements in accuracy compared to previously tabulated values and reveal fine structure in the Al L1 and L2,3 regions, with photon energy step sizes as small as 0.02 eV. The implications of this work in the successful realization of EUV/x-ray instruments and in the validation of atomic and molecular physics models are also discussed. [ABSTRACT FROM AUTHOR]

We have calculated electron backscattering coefficients, η (E p) , at primary electron energies E p of 0.1–100 keV for three elemental and intermediate atomic number solids, Cr, Co and Pd, with an up-to-date Monte Carlo simulation model. A relativistic dielectric functional approach is adopted for the calculation of the electron inelastic cross section, where several different datasets of optical energy loss function (ELF) are adopted. The calculated backscattering coefficient is found to be substantially affected by the ELF, where the influence can be seen to follow the f- and ps-sum rules and the resultant energy dependence of electron inelastic mean free path. To understand the uncertainties involved in a comparison with experimental data both the theoretical uncertainty due to the elastic cross-section model and the experimental systematic error for the contaminated surfaces are investigated. A total of 192 different scattering potentials are employed for the calculation of Mott's electron elastic cross section and this theoretical uncertainty is confirmed to be small. On the other hand, the simulation of contaminated Co and Pd surfaces with several carbonaceous atomic layers can well explain the experimental data. The present results indicate that accurate backscattering coefficient data should be either measured from fully cleaned surfaces or obtained from modern Monte Carlo theoretical calculations involving reliable optical constants data. With the recent progress in the accurate measurement of optical constants by reflection electron energy loss spectroscopy technique, constructing a reliable theoretical database of electron backscattering coefficients for clean surfaces of elemental solids is highly hopeful. [ABSTRACT FROM AUTHOR]

This review concentrates on the microstructure of InxGa1−xN layers and quantum wells (QWs) in relation to their optical properties. The microstructure of InxGa1−xN, with a constant In(x) concentration, shifts with layer thickness. Only layers below 100 nm for x = 0.1 are nearly defect-free. A photoluminescence peak is observed at 405 nm, in line with ∼10% In, suggesting band-edge luminescence. Layers with greater thickness and In content present a corrugated surface with numerous structural defects, including V-defects, causing redshifts and multi-peaks in photoluminescence up to 490 nm. These defects, resembling those in GaN, lead to a corrugated sample surface. Atomic force microscopy shows a 3.7-fold larger corrugation in samples with 20 QWs compared to those with 5 QWs measured on 2 × 2 μm2 areas. Like in GaN, dual growth on different crystallographic planes results in varied QW thicknesses, influencing optical traits of devices made from InxGa1−xN layers. The purpose of this review and the chosen subject is to highlight the significant contribution of Wladek Walukiewicz and his group to the current research on the properties of InxGa1−xN, which are crucial alloys in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

In the present paper, we apply a blind fitting algorithm to model two-dimensional energy-incidence angle maps of soft x-ray resonant reflectivity measured in nanoscale epitaxial multilayers of multiferroic ε-Fe2O3 grown by pulsed laser deposition. The possibility of fitting the spectral shape of the complex refraction index across the Fe L3 absorption edge without having an initial guess about the optical constants has been demonstrated. The spectral shape fitting of the real (f1) and imaginary (f2) parts of the atomic scattering factor has been carried out by using a specially designed software utilizing OpenCL fast calculations on graphical processing units. The Kramers-Kronig relations between f1 and f2 are automatically taken into account by the fitting algorithm. A reasonable agreement between blindly generated and reference scattering factor spectra derived independently from an x-ray absorption spectroscopy experiment has been demonstrated. The blind fitting has been compared with the alternative refinement routines, in which small free variations of the reference spectral shapes (or no variations at all) have been allowed. The presented approach to the resonant x-ray reflectometry modeling makes it unnecessary to acquire the optical constant spectral shapes in advance and, thus, is especially helpful when such spectra cannot be physically measured, e.g., for a buried layer of a multilayer system. [ABSTRACT FROM AUTHOR]

Short-period 2.5 nm W/B4C multilayers are useful as dispersive Bragg reflectors in wavelength-dispersive x-ray fluorescence. However, high roughness at the W–B4C interfaces deteriorates optical performance. To improve this, low-energy neon ion beam polishing (IBP) has been applied in sputter-deposited 2.5 nm W/B4C multilayers. Two energies, 200 and 50 eV, were investigated to study the effects of polishing by sputter removal (200 eV) and polishing by the mobilization of weakly bound surface atoms (50 eV). Atomic force microscopy and x-ray scattering showed reduced interface roughness for both IBP energies. However, the optical constant profile of 200 eV IBP showed strong W–B4C intermixing and interface asymmetry, leading to significant reflectance loss. In contrast, 50 eV IBP resulted in sharp, symmetric interfaces and increased optical contrast. A 43% peak reflectance at θ = ⁓9.7° grazing for W/B4C with 50 eV IBP was measured at λ = 0.834 nm—a 6.4% increase relative to non-polished W/B4C, corresponding to a 25% increase in integrated reflectance. These results highlight the necessity of using low-energy ion polishing by the mobilization of weakly bound surface atoms in short-period multilayers—rather than polishing by sputter removal. [ABSTRACT FROM AUTHOR]

A validated method based on Haidinger fringes has been proposed to measure the optical constants for thin-walled glass cells. The method can significantly enhance measurement accuracy by utilizing the reflected spectrum to determine the optical constants of the sample. The reflected light off the inner and the outer surfaces of the cell combined together and formed the interferential pattern (Haidinger fringes) detected by the photodiodes. Taking into account that the sample in our experiment is a sealed cell, we deliberately set the incident angle to a non-zero value. First, the measurement principle has been analyzed, and subsequently, the relevant experimental platform has been established. To reduce random errors, we recalibrated the relationship between the frequency of the laser and the operating temperature. Furthermore, the incident angle has been accurately estimated using the method of non-linear least squares. Finally, the weighted average, considering correlated uncertainties for all measurements, is 1.873 ± 0.005 016 mm, which showcases clear advantages over conventional mechanical methods that risk potential damages. [ABSTRACT FROM AUTHOR]

In this study, biopolymer composites based on chitosan (CS) with enhanced optical properties were functionalized using Manganese metal complexes and black tea solution dyes. The results indicate that CS with Mn2+-complexes can produce polymer hybrids with high absorption, high refractive index and controlled optical band gaps, with a significant reduction from 6.24 eV to 1.21 eV. The refractive index and optical dielectric constant measurements show that the doped CS films have more charge carriers and traps than those in pure CS films. The Lorentz-Drude model was used to derive several significant optical parameters, and the W-D model was utilized to calculate the optical moments M-1 changing from 0.35 to 2.13 and M-3 changing from 0.005 to 0.4. It was shown that the doped samples have larger Urbach energy than pure film, increased from 0.29 to 0.55 eV. Tauc and ASF model was also used to calculate the electronic transitions, band structure, and optical characteristics. Bandgap energy based on Tauc model at m = 2, 1/3, 1/2, and 2/3 are 1.77, 1.54, 1.47, and 1.37 eV, based on ASF model are 1.52, 1.42, 1.69, and 1.47 eV, respectively. As a result of changes in the optical diffraction parameters the optical mobility () changed from 1.67 to 1.27 and optical resistivity from 9.36 × 10–27 to 4.0 × 10–29. The dopped samples show an increase in their linear optical susceptibility, third-order nonlinear optical susceptibility and nonlinear refractive indices, changing from 3.165 × 10–15 to 2.831 × 10–12 esu. Finally, light propagation velocities, surface resistance, and thermal emissivity were also examined. [ABSTRACT FROM AUTHOR]

The physical characteristics of quaternary ternary glass, which is based on sulfur and contains copper, are the main topic of the investigation. Ge 3 S 6 Ag 1-x Sn x chalcogenide glasses were fabricated using the conventional melt-quench method. With an increase in concentration of Sn, it was observed that the glass's density (ρ) decreased but the molar volume (V m) increased. Transmittance and reflection measurements of the films were made over a range of 0.30–2.5 μm. The estimated envelopes (upper (R M) and lower (R m)) of the reflection spectrum might be used to determine the complex index of refraction (real (n) and imagery (k)) and the film thickness (t). There was a matching decrease in the index of refraction (n) and an increase in the optical gap (E g) for increasing concentrations of tin. Further information on results pertaining to refraction loss, plasma frequency, and electronic polarizability was also supplied by the study. The effects of varying concentrations of tin on the film's nonlinear index of refraction (n 2), 3ed order susceptibility (ꭓ(3)), and nonlinear absorption coefficient (ꭓ a) were investigated further. In Ge 3 S 6 Ag 1-x Sn x system, the values of n 2 , third-order susceptibility ꭓ(3), and nonlinear absorption coefficient ꭓ a decrease with the addition of tin, which replaces Ag atoms with higher density and atomic radius. Finally, the films analyzed in our work exhibit interesting properties for application in various optical devices. [ABSTRACT FROM AUTHOR]

In this study, TiO2-P25 films on FTO substrates were synthesized using the sol-gel process and studied using Variable Angle Spectroscopy Ellipsometry (VASE) to determine their optical constants and thickness. The measurements were carried out at room temperature in the wavelength range of (300–900) nm at incident angles varying from 55° to 70°. The resulting thicknesses were found to be around 1000 nm. A graded layer model, which allowed for accurate representation of the depth-dependent optical variations, was employed to model the properties of these TiO2-P25 films. This modeling approach provided deeper insights into the internal structure of the films, particularly how the graded structural characteristics impact the overall optical behavior. Understanding these depth-dependent variations is essential for optimizing the use of TiO2-P25 films in technologies such as solar cells and optical devices. [ABSTRACT FROM AUTHOR]

van der Waals materials support numerous exotic polaritonic phenomena originating from their layered structures and associated vibrational and electronic properties. However, many van der Waals materials' unique properties are most prominent at cryogenic temperatures. This presents a particular challenge for polaritonics research, as reliable optical constant data are required for understanding light-matter coupling. This paper presents a cryogenic Fourier transform infrared microscope design constructed entirely from off-the-shelf components and associated fitting procedures for determining optical constants in the infrared. Data correction techniques were developed to directly quantify systematic errors in the fitting procedure. We use this microscope to present the first temperature-dependent characterization of the optical properties of hexagonal boron nitride enriched with isotopically pure boron. Our full analysis of the infrared dielectric function shows small but significant tuning of the optical constants, which is highly consistent with Raman data from the literature. We then use this dielectric data to perform and analyze the polariton propagation properties, which agree exceptionally well with published cryogenic scattering-type near-field microscopy results. In addition to the insights gained into hyperbolic polaritons in hBN, our paper represents a transferable framework for characterizing exfoliated infrared polaritonic materials and other infrared devices. This could accelerate discoveries in different material systems, especially those that are spatially inhomogeneous or cannot be prepared as large single crystals. [ABSTRACT FROM AUTHOR]

The study highlights the significant effects of Zn ions concentration on the optical properties of BaNi2-xZnxFe16O27 ferrites, emphasizing the tunability of the band gap through Zn doping and explores their potential to enhance their optical properties. The barium-nickel ferrite powder, with the composition BaNi2−xZnxFe16O27, was synthesized using the ceramic method. The effects of Zn doping were analyzed using X-ray diffraction (XRD) and UV‒visible (UV–Vis) spectroscopy. XRD confirmed a pure single-phase W-type hexagonal structure, with an increase in both grain size and lattice constant proportional to the Zn content. The optical properties were assessed through UV‒visible spectroscopy, revealing an increaseing of the band gap with increasing Zn concentration, confirming material's semiconducting behavior.All optical constants, exhibited consistent variation with increasing Zn substitution.. Additionally, both electrical and optical conductivities increased with rising photon energy, while the conductivity peak decreased with higher Zn content. The electric susceptibility was found to decrease as Zn concentration increased. The results indicate that Zn doping leads to significant changes in lattice parameters, crystallite size, and bandgap energy, suggesting potential applications in optoelectronics, photonics devices, and energy storage." [ABSTRACT FROM AUTHOR]

With the unique physical and chemical properties, WS2 shows great potential for applications in the fields of electronics and optics. Based on the first-principles calculations of density functional theory, the aim of this paper is to investigate the electronic structure and optical properties of single 4d transition metal atoms X (X = Nb, Mo, Tc, Ru, Rh, Pd) substitutionally doped monolayer WS2 . The results show that the transition metal atoms doped WS2 systems are all exothermic and stable, and the decrease of the band gap width leads to the enhancement of conductivity and significant changes in electronic structure. For these doped metal atoms, Nb doped WS2 exhibits metallicness, Ru doped WS2 exhibits semi-metallicness, and Tc, Rh and Pd doped WS2 induce magnetism. The dielectric constant and optical refractive index of Nb, Ru, Rh and Pd doped WS2 systems increase. The WS2 systems before and after doped have good transparency characteristics, and the absorption spectrum is red shifted. The absorption of Nb, Ru and Rh doped WS2 is enhanced in the infrared region, and the absorption of Nb, Rh and Pd is enhanced in the visible region. Especially, the Pd doped WS2 has the best absorption effect in the visible region, which has a certain potential for application in the photodetector. [ABSTRACT FROM AUTHOR]

The aim of this study is to address the problems of oil mixing during the sequential transportation of refined oil and the influence of temperature on the quality detection of refined oil. To better detect the quality of refined oil, UV-Visible transmission spectroscopic experiments of 92# gasoline, diesel oil, and their mixtures at different temperatures are performed. Then, the influence of temperature on the transmission spectrum is analyzed, and the transmittance–temperature compensation equations are obtained. Based on the double-thickness inversion model, the optical constants of the mixed refined oil at UV-Visible wavelengths are obtained, and the effect of temperature on the optical constants is analyzed. For a specified optical range, the transmittance of the mixed refined oil gradually increases with increasing temperature. The temperature has a certain effect on the optical constant of the refined oil; moreover, the relationships between the transmittance of the refined oil and the change in temperature are obtained at 364, 378, and 394 nm; these wavelengths are selected based on a combination of characteristic spectra calculated by a genetic algorithm. The obtained relationship can effectively remove the influence of temperature changes on the transmittance spectra of refined oil to improve the accuracy of detection. [ABSTRACT FROM AUTHOR]

The produced glasses with the chemical formula 60B2O3–20Na2O–15ZnO–5Bi2O3–XCeO2, with X = 0.0 (Ce-0.0)—0.9 (Ce-0.9) mol% glasses have been studied in terms of their physical, optical, and dielectric properties. Densities (ρ) ranged from 3.16 g/cm3 to 3.29 g/cm3. The absorbance spectra revealed that the broad near-visible band for the Ce-0.0 sample had a central wavelength of λcutoff = 430.03 nm, but for the Ce-0.9 glass sample, it shifted towards a higher wavelength of λcutoff = 548.63 nm. The direct optical band gap ( E g Direct ) decreased From 3.10 eV to 2.52 eV and the indirect optical gap ( E g Indirect ) declined from 2.95 eV to 2.22 eV. Urbach's energy (EU) values decreased from 0.273 eV to 0.211 eV as the CeO2 content in the glass network increased, although refractive index (n) values increased from 2.39 to 2.60. With an increase in CeO2 content, the Ce-X glasses' molar polarizability (αm) and molar refraction (Rm) were improved. The generated glasses' dielectric spectroscopy is examined at room temperature at frequencies ranging from 50 Hz to 5 MHz in order to assess the chemical modifications caused by cerium doping on dielectric spectroscopy elements such the dielectric constant (ɛ′) and tangent loss (tan δ). The ε′ of all the glasses loaded with various concentrations of cerium decreases significantly as the frequency rises during the low frequency interval. The energy absorption (EABF) and exposure (EBF) accumulation factors had their lowest values at 1 MFPs and their highest values at 40 MFPs. The samples with Ce-0.9 possessed the lowest values of relaxation length (λFRNCS) and half value layer (HVLFRNCS). The suggested glasses can be used in various optoelectronics and electrical devices. [ABSTRACT FROM AUTHOR]

The paper is devoted to studying the possibilities of sub-terahertz ellipsometry to determine the technological characteristics (porosity and moisture content) of activated carbon granules as a working medium for air filters, including ventilation systems of nuclear power plants. Samples with a flat surface of sufficient size for ellipsometric measurements were formed from vertically located close-packed granules. Two types of industrial granules of different sizes were investigated. The applicability of various surface models and effective media for processing experimental ellipsometric data is considered. For the first time, it was proposed to use a model of an effective medium with a screening factor depending on the angle of incidence to analyze ellipsometric data. An algorithm to simultaneously determine the porosity and moisture content of activated carbon granules was developed and tested. The moisture range was determined, within which sub-terahertz ellipsometry allows one to unambiguously determine both required parameters and in which—only porosity. The obtained results are corroborated by independent experimental and theoretical methods and consistent with the data provided by the manufacturers of the materials under study. In general, the effectiveness of sub-terahertz ellipsometry has been demonstrated for rapid assessment of the characteristics of activated carbon granules to determine the condition and predict the service life of carbon air filters. The proposed model of the effective medium with a variable screening factor can be used to study other objects with a similar structure. [ABSTRACT FROM AUTHOR]

Thickness and optical constants of transparent conducting oxide (TCO) of metal oxide thin films have been commonly estimated by invoking theoretical models based on measured optical reflectance or transmittance. One of such widely employed models is reflectance‐based Kushev model. However, the relatively higher value of the absorption coefficient at the absorption edge of TCOs of metal oxide thin films results in a large deviation of their thickness values estimated by this model. To address the underlying problems, in the present work, we have improved the Kushev model. Specifically, for minimizing the error in the estimated thickness values from the proposed model, we have employed t test for discarding outliers of a set of thickness values of a given thin film, which were calculated from nearby extrema of a reflectance curve. Then the thickness calculated from model was validated by comparing the value of ZnO thin transparent films extracted from ellipsometric measurement. Our model shows excellent agreement with the thickness values of ZnO films from ellipsometric measurement with only 1.2% deviation. Furthermore, observed values were also compared with the values from already established Cauchy model. The perfectly matching of the simulated reflectance spectra from the present model with the measured reflectance and excellent agreement of thickness values derived from the ellipsometric measurements with the values extracted from the model may infer us that the present model is suitable for fairly accurately estimating film thicknesses of TCO thin films. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive investigation into the intrinsic properties of RNi4P12 (where R = Sm, Eu) filled skutterudite, employing the full-potential linearized augmented plane wave method within density functional theory (DFT) simulations using the WIEN2k framework. Structural, phonon stability, mechanical, electronic, magnetic, transport, thermal, and optical properties are thoroughly explored to provide a holistic understanding of these materials. Initially, the structural stability of SmNi4P12 and EuNi4P12 is rigorously evaluated through ground-state energy calculations obtained from structural optimizations, revealing a preference for a stable ferromagnetic phase over competing antiferromagnetic and non-magnetic phases. Electronic properties are further investigated using a combination of computational schemes, including Generalized Gradient Approximation (GGA) and Trans-Bhalla modified Becke Johnson (TB-mBJ), effectively handling the f-electrons. Both approximations reveal intriguing metallic behavior in both spin-up and spin-down channels. The focus is on Ni-P-based filled skutterudite, featuring localized 4f and 5d-electrons, which exhibit dense energy bands near the Fermi energy, originating from rare earth and Ni-atoms. The dense density of states near the Fermi energy suggests suitability for thermoelectric applications. Additionally, spin-polarized band structures unveil significant net magnetism, indicating potential applications in spintronics. Elastic parameters are estimated using the Voigt-Reuss-Hill approximation, with elastic stability crucial for practical applications, characterized by brittleness indicating the compounds' ability to deform without fracturing under stress. Finally, transport and thermal properties are analyzed, providing insights into conductivity and heat dissipation characteristics. Optical constants, including dielectric function, optical reflectivity, refractive index, electron energy loss, and optical conductivity, are calculated for photon energy radiation. Overall, this study offers a comprehensive understanding of the multifaceted properties of SmNi4P12 and EuNi4P12-filled skutterudite, laying the groundwork for their potential applications in various fields. [ABSTRACT FROM AUTHOR]

Optically controllable delivery of microparticles excites interesting research and applications in various fields because of the noninvasive and noncontact features. However, long-distance delivery with a static low-power light source remains challenging. Here, the constant-force photonic projectile (CFPP) is employed to achieve long-distance delivery of microparticles with a low-power laser beam. The CFPP takes advantage of photon absorption to create a constant optical force within a large range, surpassing traditional tweezers. The concept of CFPP has been experimentally corroborated by remote control over micrometer-sized absorptive particles (APs) using a simple tilted focused beam. At the laser focus, strong photon absorption results in a large constant optical force that ejects the APs along the optical axis. Furthermore, the additional thermal convection field, which attracts particles from a distance into the working range of the CFPP, is utilized to collect the unbound APs for reuse. Finally, we demonstrate the concept of drug delivery by transporting a small microparticle onto a host particle at a remote location. The proposed CFPP provides a new perspective for drug delivery and heat-enhanced photodynamic therapy. [ABSTRACT FROM AUTHOR]

Interband cascade lasers (ICLs) are becoming increasingly valuable in mid-infrared applications due to their low power consumption and compatibility with silicon photonic integration, particularly for trace gas sensing. ICLs have demonstrated room-temperature continuous-wave operation in the 3–6 μm range, with excellent performance around 3.3 μm. A key factor limiting ICL performance at longer wavelengths is optical loss, i.e., caused by the intervalence band transitions. These losses increase with hole concentration in the active region, leading to a pronounced current-dependence of the optical losses in ICLs. Conventional methods that infer optical losses from length-dependent variations in parameters such as slope efficiency or threshold current require the assumption of constant optical loss. In this study, we present a direct optical transmission measurement technique to determine waveguide losses. Our experiments confirm strongly increasing waveguide losses with current density, directly impacting the quantum efficiency of ICLs. This approach offers a precise evaluation of optical losses and bears a functional alternative compared to traditional methods, addressing the limitations of assuming constant losses and providing enhanced insight into ICL performance across various wavelengths. [ABSTRACT FROM AUTHOR]

In this research, we investigated the optical properties of CdSe thin films on glass substrates using spectroscopic ellipsometry. The samples were analysed using an M-2000 rotation compensator spectroscopic ellipsometer at room temperature, covering a photon energy range of 1.5-7.0 eV. We used an appropriate dispersion model to obtain the spectral dispersion of the optical constants. We calculated the thickness, dielectric permittivity (real and imaginary parts), refraction, and extinction coefficients of the thin layers. The results showed high transparency that varied with the size of the CdSe thin films. Additionally, we determined the bandgap width for samples with thicknesses of 350 nm and 400 nm, which were produced using the chemical deposition method. [ABSTRACT FROM AUTHOR]

Sodium borate glasses doped with Nd3+ ions and having the molar formulations 75B 2 O 3 – 15Na 2 O – 9.5x – 0.5Nd 2 O 3 , where x = Bi 2 O 3 ; SrO and Li 2 O were prepared by employing the melt quenching technique. The glasses were coded as BiNd, SrNd, and LiNd for x = Bi 2 O 3 ; SrO and Li 2 O, respectively. The prepared glasses were characterized for their physical and optical attributes. The influence of the glass composition on the photoluminescence and fast neutron (FN) and charged radiation (CR) transmission efficiencies were also investigated. The density of BiNd, SrNd, and LiNd is 3.32, 2.43, and 3.32 g/cm3, respectively. Optical constants of the glasses showed variations with glass composition. The FTIR study of the glass also revealed the structure of the glasses. The BiNd glass has the most intense PL of all the samples, followed by SrNd glass, while LiNd had the weakest PL emission. The value of Σ R for BiNd, SiNd, and LiNd is 0.1029 cm−1, 0.1009 cm−1, and 0.0987 cm−1, respectively. The projected ranges of electrons, protons, helium ions, and carbon ions were generally lower for denser XNd glass. The XNd glasses are potentially useful of optical, shielding and dosimetry applications. [ABSTRACT FROM AUTHOR]

Polymethyl methacrylate (PMMA)/Congo Red (CR) and polyvinyl chloride (PVC)/CR composite films were prepared on optical glass by the drop method for optical measurements and also prepared as tablets under pressure for dielectrical measurements. The optical transmission spectra measurements for PMMA and PVC film doped with CR showed a highly absorption in the ultraviolet-visible (UV-Vis) optical range (at 353 nm and 518 nm) and considerably blocking in broad visible range (190 nm–640 nm). PMMA/CR and PVC/CR composite films containing congo red at a concentration of 1 wt% showed maximum absorption bands at 290 nm and 416 nm, but their transmittance percentages were reasonably reduced compared to those of pure PMMA and PVC. Both of composites indicated high transmittances between 640 nm and 800 nm. The optical constants of the PMMA/CR and PVC/CR composite films such as optical band energy gaps (Eg) estimated using Tauc's model, refractive index and reflectance (%) were calculated. UV–Vis, Fourier transform infrared spectroscopy (FTIR) and Thermogravimetry Analysis (TGA) measurements were used to confirm the breakdown of the -N = N- azo group bonds attached to the aromatic ring as a result of thermal decomposition of CR at 500 °C, and it was suggested that N2 gas was eliminated from the CR above 360 °C. The dielectric plots showed that the dielectric constant increased when the CR is doped up to 70 wt% in the polymer matrices. A further increase in the doping concentration of CR resulted in an increase of the dielectric constant. The dielectric constant decreased with an increase in the frequency for all of the samples. The ac (alternating current) conductivity values of PMMA and PVC showed an increase with increasing CR dopant in the polymer composites, while the ac conductivity values were found to be values between those of the pure polymers and CR. [ABSTRACT FROM AUTHOR]

This work presents the optical properties of nickel zinc ferrite, nickel copper zinc ferrite, and nickel cobalt zinc ferrite films prepared on Si/SiO2 substrates using the sol-gel and spin-coating technique. A J.A. Woollam Company RC2 model D variable angle spectroscopic ellipsometer was used to measure the amplitude ratio (Ψ) and phase difference (Δ) of the films annealed at two distinct temperatures (500 and 800 °C). Measurements were taken at three incident angles (55°, 65°, and 75°) across the spectral range of 190–1000 nm, with a step size of 1 nm. The acquired data were subjected to modeling using a summation of Kramers–Kronig consistent oscillators to determine the film thickness and complex optical functions (refractive index and extinction coefficient) with a minimized mean-squared error. Additionally, incorporating a surface roughness layer notably enhanced the accuracy, with the roughness described using the Bruggeman effective medium approximation reflecting a 50%–50% mixture between the film's optical constants and those of air (void). The experimental and simulated (Ψ, Δ) spectra as a function of wavelength at angles 55°, 65°, and 75° for the NZF, NCuZF, and NCoZF films annealed at 500 and 800 °C are provided. The refractive index and extinction coefficient values as a function of wavelength for NZF, NCuZF, and NCoZF films annealed at 500 and 800 °C are also included. The elucidated optical properties of these films hold potential for application in various optoelectronic devices, including solar cells. [ABSTRACT FROM AUTHOR]

Reactive sputtering is a very useful technique, particularly, for producing inhomogeneous interference filters, where the refractive index changes smoothly during deposition. In such a context, precise control of deposition parameters is crucial for replicating the desired optical properties. This study employed a pulsed DC power source to investigate the influence of a duty cycle on target poisoning, sputtering plasma characteristics, electric signals, and optical and morphological properties of synthesized films. Reactive pulsed DC magnetron sputtering was characterized by analyzing the behavior of plasma emission via optical emission spectroscopy and voltage-current signals, while modulating parameters such as the oxygen content within the vacuum chamber. A set of thin films was coated on glass substrates under different system conditions. These films underwent characterization employing spectroscopic ellipsometry to ascertain their optical constants, atomic force microscopy for surface morphology analysis, and x-ray diffraction for the determination of crystalline structures. The results indicate that longer duty cycles required higher oxygen levels to poison the target. Additionally, a detailed analysis of electrical signals revealed nonsquare waveforms, whose characteristics were influenced by both the duty cycle and the oxygen content within the sputtering chamber, resulting in higher effective voltages during the on-time of the voltage pulse. Grown films via reactive pulsed DC magnetron sputtering were also compared to films grown via conventional DC magnetron sputtering at equivalent conditions of target poisoning. [ABSTRACT FROM AUTHOR]

Tungsten oxide (WO3) electrochromic devices are obtaining increasing interest due to their color change and thermal regulation. However, most previous work focuses on the absorption or transmission spectra of materials, rather than the optical parameters evolution in full spectrum in the electrochromic processes. Herein, we developed a systematic protocol of ex situ methods to clarify the evolutions of subtle structure changes, Raman vibration modes, and optical parameters of WO3 thin films in electrochromic processes as stimulated by dosage-dependent Li+ insertion. We obtained the below information by ex situ spectroscopic ellipsometry. (1) Layer-by-layer Li+ embedding mechanism demonstrated by individual film thickness analysis. (2) The details of its optical leap in the Brillouin zone in the full spectral. (3) The optical constants varied with the Li+ insertion in the ultraviolet, visible, and near-infrared bands, demonstrating the potential for applications in chip fabrication, deep-sea exploration, and optical measurements. (4) Simulated angular modulation laws of WO3 films for full spectra in different Li+ insertion states. This ex situ method to study the optical properties of electrochromic devices are important for monitoring phase transition kinetics, the analysis of optical leaps, and the study of ion diffusion mechanisms and the stoichiometry-dependent changes in optical constants over the full spectral. This work shows that electrochromic films in Li+ surface permeation can be applied in the field of zoom lenses, optical phase modulators, and other precision optical components. Our work provides a new solution for the development of zoom lenses and a new application scenario for the application of electrochromic devices. [ABSTRACT FROM AUTHOR]

Typical titanium oxide (TiO2) films are transparent in the visible range, allowing for their index of refraction and thickness to be extracted by single-angle spectroscopic ellipsometry (SE) using a Cauchy model. However, TiO2 films grown by atomic layer deposition (ALD) from tetrakis(dimethylamino)titanium (IV) (TDMAT) and H2O at 350 °C absorb in the visible range due to the formation of Ti-O-N/Ti-N bonds. Single-angle SE is inadequate for extracting the optical constants of these films, as there are more unknowns (n, k, d) than measurable parameters (ψ, Δ). To overcome this limitation, we combined SE with transmission (T) measurements, a method known as SE + T. In the process, we developed an approach to prevent backside deposition on quartz substrates during ALD deposition. When applying a B-spline model to SE + T data, the film thicknesses on the quartz substrates closely matched those on companion Si samples measured via standard lithography. The resulting optical constants indicate a reduced refractive index, n, and increased extinction coefficient, k, when compared to purer TiO2 thin films deposited via a physical vapor deposition (PVD) method, reflecting the influence of nitrogen incorporation on the optical properties. [ABSTRACT FROM AUTHOR]

Recently, the Fabry–Perot (F–P) cavity electrochromic devices, which are constructed by combining nano-size inorganic electrochromic material WO 3 and reflective metal layers, have attracted considerable attention due to their potentials in the fields of dynamic multicolor displays and active camouflage. However, in the few studies that have been reported, the peak reflectance of flexible F–P cavity multicolor electrochromic devices in the visible wavelength band is generally lower than 30 %, which limits their reflective display and camouflage effects in high-brightness environments. Thus, we have combined multicolor reflective electrochromic electrodes in WO 3 /Au asymmetric F–P nanocavity constructed by magnetron sputtering on a Nylon 66 porous substrate with a highly transparent UV-cured gel electrolyte and a PET plastic sealing procedure. As a result, a flexible and dynamic multicolor electrochromic skin with high reflectance (R max ＞50 %) and excellent flexibility (bending radius of 4 mm) has been fabricated. The WO 3 electrochromic layer at the top works as the dynamic dielectric layer in the broadband absorption Fabry–Perot cavity, and the inert metal Au layer at the bottom works as the reflective layer. The WO 3 /Au asymmetric F–P cavity can acutely capture the variation in optical constants of WO 3 due to the thickness change and electric-driven effects. This cavity facilitates the selective reflection and absorption of the energy distribution of the spectrum after the induced interferometric resonance. As a result, the cavity exhibits a rich array of structural colors, including ocher, taupe, yellow, orange, green, and violet. The electrochromic skin exhibits a fast switching time and maintains 99.43 % of the optical modulation amplitude (ΔR) after 110 coloring/bleaching cycles. It provides a potential option in the field of flexible high-brightness reflective displays and dynamic camouflage in the future. [ABSTRACT FROM AUTHOR]

Context. The inner disk of the young star PDS 70 may be a site of rocky planet formation, with two giant planets detected further out. Recently, James Webb Space Telescope/Mid-Infrared Instrument (JWST/MIRI) Medium-Resolution Spectrometer (MRS) observations have revealed the presence of warm water vapour in the inner disk. Solids in the inner disk may inform us about the origin of this inner disk water and nature of the dust in the rocky planet-forming regions of the disk. Aims. We aim to constrain the chemical composition, lattice structure, and grain sizes of small silicate grains in the inner disk of PDS 70, observed both in JWST/MIRI MRS and the Spitzer Infrared Spectrograph (Spitzer IRS). Methods. We used a dust fitting model, called DuCK, based on a two-layer disk model considering three different sets of dust opacities. We used Gaussian random field and distribution of hollow spheres models to obtain two sets of dust opacities using the optical constants of cosmic dust analogs derived from laboratory-based measurements. These sets take into account the grain sizes as well as their shapes. The third set of opacities was obtained from the experimentally measured transmission spectra from aerosol spectroscopy. We used stoichiometric amorphous silicates, forsterite, and enstatite in our analysis. We also studied the iron content of crystalline olivine using the resonance at 23–24 μm and tested the presence of fayalite. Both iron-rich and magnesium-rich amorphous silicate dust species were also employed to fit the observed spectra. Results. The Gaussian random field opacity set agrees well with the observed spectrum, better than the other two opacity sets. In both MIRI and Spitzer spectra, amorphous silicates are the dominant dust species. Crystalline silicates are dominated by iron-poor olivine. The 23–24 μm olivine band peaks at 23.44 μm for the MIRI spectrum and 23.47 μm for the Spitzer spectrum, representing around or less than 10% of iron content in the crystalline silicate. In all of the models, we do not find strong evidence for enstatite. Moreover, the silicate band in the MIRI spectrum indicates larger grain sizes (a few microns up to 5 μm) than the Spitzer spectrum (0.1–1 μm), indicating a time-variable small grain reservoir. Conclusions. The inner PDS 70 disk is dominated by a variable reservoir of warm (T~350–500 K) amorphous silicates, with ~15% of forsterite in mass fraction. The 10μm and 18μm amorphous silicate bands are very prominent, indicating that most emission originates from optically thin dust. We suggest that the small grains detected in the PDS 70 inner disk are likely transported inward from the outer disk as a result of filtration by the pressure bump associated with the gap and fragmentation into smaller sizes at the ice line. Collisions among larger parent bodies may also contribute to the small grain reservoir in the inner disk, but these parent bodies must be enstatite-poor. In addition, the variation between MIRI and Spitzer spectra can be explained by a combination of grain growth over 15 years and a dynamical inner disk where opacity changes occur resulting from the highly variable hot (T~1000 K) innermost dust reservoir. [ABSTRACT FROM AUTHOR]

In this paper, we used meteorological data to simulate vertical profiles of optical turbulence at the Special Astrophysical Observatory (SAO) (Russia, 43°40′19″ N 41°26′23″ E, 2100 m a.s.l.), site of the 6 m Big Telescope Alt-azimuthal. For the first time, the vertical profiles of optical turbulence are calculated for the SAO using ERA-5 reanalysis data. These profiles are corrected using DIMM measurements as well as estimations of atmospheric boundary layer heights. We may note that the method basically reconstructs the most important features of the shape of the measured profile under clear sky. Atmospheric turbulent layers were identified, and the strength of optical turbulence in these layers was estimated. The model hourly values of seeing corresponding to the obtained vertical profiles range from 0.40 to 3.40 arc sec; the values of the isoplanatic angle vary in the range from 1.00 to 3.00 arc sec (at λ = 500 nm). The calculated median of seeing is close to 1.21 arc sec. These estimations are close to the measured median of seeing (1.21 arc sec). [ABSTRACT FROM AUTHOR]

The current study aims to synthesize of poly-methyl methacrylate (PMMA)-polyethylene glycol (PEG) doped with tin oxide (SnO2) and silicon carbide (SiC) nanostructures for gamma ray attenuation and photonics applications. The microstructure and optical characteristics of PMMA-PEG-SnO2-SiC nanostructures were studied. The obtained results indicated that the PMMA-PEG absorbance increased of 69.6% and the transmittance decreased of 46% when the SnO2/SiC NPs ratio rise to 4.8 wt%. The PMMA-PEG's energy gap (Eg) decreased to 3.95 eV when the SnO2/SiC NPs ratio reached of 4.8 wt%. The optical constants (coefficient of absorption (α), index of refractive (n), coefficient of extinction (k), real (ε1) and imaginary (ε2) parts of dielectric constants, and conductivity of optical (σop) were increased of 69.6%, 22.1%, 69.6%, 39.4%, 76.3, and 76.3%, respectively, when SnO2/SiC NPs reached of 4.8 wt% at wavelength (λ = 540 nm). These results make the PMMA-PEG-SnO2-SiC nanostructures are appropriate for optical and electronic applications. Finally, the gamma radiation attenuation coefficients were increased with rising nanoparticles concentrations. The (PMMA-PEG-SnO2-SiC) nanostructures have highest attenuation coefficients for gamma radiation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She 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.)

The optical constants of single-crystal AlxGa1−xP and AlxGa1−xAs have been widely studied at various Al compositions but have not yet been thoroughly investigated as polycrystalline materials. Using variable-angle spectroscopic ellipsometry, we estimate and analyze the optical constants of polycrystalline Al0.25Ga0.75P and Al0.9Ga0.1As that were non-epitaxially deposited at deposition temperatures of either 250 or 420 °C, and with various dopant species, dopant concentrations, and V/III flux ratios. For wavelengths of 350–400 nm, decreasing the V/III ratio increases the refractive index of Be-doped polycrystalline Al0.25Ga0.75P. For wavelengths >500 nm, as the targeted Be dopant concentration increases for polycrystalline Al0.25Ga0.75P, the amount the extinction coefficient increases and the indirect bandgap decreases depends on the V/III ratio. Furthermore, Si-doped polycrystalline Al0.25Ga0.75P has significantly smaller extinction coefficient values than when it is Be-doped, for the same V/III ratio and targeted doping concentration, at wavelengths >500 nm. Based on our findings, we hypothesize that the dopant species, dopant concentration, and the V/III ratio dictate various types of defect concentrations, which then affect the optical constants and indirect bandgap of polycrystalline Al0.25Ga0.75P. Additionally, for wavelengths >500 nm, we find that polycrystalline Al0.25Ga0.75P and Al0.9Ga0.1As have the lowest extinction coefficient values when deposited at 420 °C, as opposed to 250 °C. Thus, we hypothesize that the deposition temperature is the most significant factor in dictating the optical constants of these polycrystalline III-Vs. Ultimately, this work demonstrates alternative methods to tune the optical constants of polycrystalline Al0.25Ga0.75P and Al0.9Ga0.1As, as opposed to tuning the Al composition. [ABSTRACT FROM AUTHOR]

The low-temperature optical properties of a SrTiO3 crystal doped with 0.7% wt. Nb and a pure SrTiO3 reference crystal were studied using spectroscopic ellipsometry. The optical constants and dielectric functions were obtained in the spectral range of 0.8–8.8 eV at temperatures from 10 to 300 K, and the optical conductivity was obtained in the spectral range of 0.03–1 eV at 300 K. Analysis of the optical conductivity spectra in the infrared spectral range confirmed the presence of free electrons and additional absorption hump between 0.1 and 0.4 eV (806 and 3226 cm−1) in doped SrTiO3 and optical phonons in both doped and undoped SrTiO3. The performed analysis of optical absorption spectra in the range 0.8–8.8 eV revealed frustration of the indirect bandgap and an increase in the direct bandgap energy by ∼0.03 eV in Nb-doped SrTiO3, compared to undoped SrTiO3 over the whole temperature range. The energies of the peaks' maxima of the dielectric function spectra did not significantly differ for doped and pure SrTiO3. For both Nb-doped and pure SrTiO3, temperature dependence of the direct bandgap energy and that of the index of refraction showed inflection between 100 and 150 K, which may be considered evidence of an antiferrodistortive phase transition from a cubic to a tetragonal structure. [ABSTRACT FROM AUTHOR]

Improving coating technology and thin film formation by optimizing the experimental parameters has become essential for various industrial and technological fields. This work aims to study the influence of the precursor materials on the physical and electro-optical properties of Cr2O3 thin films. The solutions were prepared using the sol–gel route and deposited on glass slides using the spin coating technique. The structure and morphology of the films were studied using XRD, FT-infrared (IR), and field-emission scan-electron microscope. The results indicated the formation of a high-purity Cr2O3 (Eskolaite) phase in the form of spherical nanoparticles with sizes of 17–25 nm. Three bands appear at 490, 765, and 889 cm−1{{\rm{cm}}}^{-1} in the FTIR spectra, which are attributed to Cr–O{\rm{Cr}}{\rm{\mbox{--}}}{\rm{O}}/ Cr═O{\rm{Cr}}{\rm{═}}{\rm{O}} vibrations. The I–V curves showed linear behavior and good ohmic features. Ultraviolet-visible-near infrared spectra showed that the films are highly transparent, with band gaps in the range of 2.60–2.90 eV, and refractive indices in the range of 1.92–2.25. The sheet resistances, the new figure of merit, the real and fictional dielectric constants, and the optical conductivity were discussed. The Cr2O3 thin films are the best candidates for various utilizations, including solar cells, sensors in the IR region, and energy storage.

In printed electronics, nanosecond pulsed laser scanning ablation is used to repair misprinted conductive silver (Ag) nanoparticle (NP) lines. Nanosecond-pulsed laser ablation is a thermal process influenced by the thermal dissipation of the substrate. In this study, we investigated the influence of the thermal properties of the substrate on the scanning ablation of Ag NP layers using a 532 nm Nd:YAG laser. We examined the ablation aspects of nanosecond pulsed scanning ablation of Ag NP layers on polyimide (PI), glass, and crystalline silicon (Si) substrates. The dried Ag NP layers and Ag NP layers that were sintered at 100, 150, and 200 °C were compared. No significant difference was observed between the ablation thresholds of the Ag NP on PI and glass substrates at all sintering temperatures. However, when the sintering temperature was 150 and 200 °C, the ablation thresholds of Ag NP on Si substrate were 371 and 435 mJ/cm2, which are noticeably larger than the 284 and 355 mJ/cm2 of 150 and 200 °C sintered Ag NP on PI substrate and 273 and 349 mJ/cm2 of 150 and 200 °C sintered Ag NP on glass substrate. Qualitative and quantitative explanations of the observed trends were provided. [ABSTRACT FROM AUTHOR]

Raman lasers are an actively developing field of nonlinear optics aiming to create efficient frequency converters and various optical sensors. Due to the growing importance of ultracompact chip‐scale technologies, there is a constant demand for optical device miniaturization; however, the development of a nanoscale Raman laser remains a challenging endeavor. In this work, a fully subwavelength Raman laser operating in visible range is proposed, based on a gallium phosphide nanocylinder resonator supporting a quasi‐bound state in the continuum (quasi‐BIC). The precise spectral matching of the nanoparticle high‐Q modes is performed with the pump and detuned Raman emission wavelengths. The simulations demonstrate an experiment‐ready design of Raman nanolaser with a lasing threshold expected to be as low as Pth≈21mW$P_{\mathrm{th}} \approx 21\nobreakspace \mathrm{mW}$. The proposed configuration represents the prototype of a low‐threshold Raman nanolaser with all dimensions smaller than the operational wavelength. [ABSTRACT FROM AUTHOR]

Using Chemical Bath Deposition (CBD) Method and various substrate temperatures, Fe2O3 films were successfully deposited. The produced film thickness was around (320 nm). Using X-ray diffraction, researchers may examine the polycrystalline structure of Fe2O3 thin films. These nanofilms contain strong peaks at 2θ =32.21, suggesting a preferred orientation along the (110) plane, and the grain size increases with substrate temperature, according to XRD tests. When the base temperature was raised from 350 to 450 oC, the strain parameter decreased from 31.35 to 28.43. AFM testing of the surface morphology of the deposition of material yields excellent homogenous coatings. The findings show that the average particle size of the nanoparticles ranges from (69.8 to 32.7) nm. SEM images show Fe2O3 films at (350, 400, 450) °C. Increased temperature reduces grain size, influencing morphology variations. The absorbance increases with substrate temperatures and decreases rapidly at short wavelengths, which correspond to the energy gap. The transmittance increases with increasing wavelength range. It decreases with rising substrate temperatures. The band gap values vary from 2.17 eV to 2.06 eV by increasing the substrate temperatures from 350 to 450 oC. It was discovered that the band gap reduces as the temperature of the Fe2O3 substrate increases. In addition, the optical constants for all films, including the absorption coefficient, the refractive index, and the extinction coefficient, were computed. Fe2O3 film's resistance over time at 350, 400, and 450°C for 300 ppm NO2 demonstrates oxidation effect and temperature sensitivity. Sensitivity decreases with higher base temperature due to charge carrier recombination, affecting NO2 response. [ABSTRACT FROM AUTHOR]

This paper reports the structural, optical, and electrical properties of dysprosium oxide (Dy2O3) deposited by electron beam deposition under ultra-vacuum on porous p-type GaAs. A porous GaAs layer was produced by electrochemical anodic etching of a (100)-heavily doped p-type GaAs substrate in hydrofluoric acid (HF) and ethanol C2H5OH solution. The surface topography of the elaborated Dy2O3 layer was determined based on atomic force microscopy (AFM) images. AFM studies showed that the structure and roughness of the Dy2O3 layer were strongly dependent on the roughness and surface of porous GaAs. Dy2O3 is polycrystalline and exhibits a cubic crystalline structure, as confirmed by x-ray diffraction (XRD) analysis. The optical properties of Dy2O3/p-porous GaAs were analyzed using various techniques including ellipsometry and photoluminescence (PL) to obtain information on surface and interface quality, bandgap, optical constants, dielectric constant, and thickness. The photoluminescence (PL) spectra revealed an intense peak at 835 nm and additional weak emission peaks at 473 nm and 540 nm, respectively. The observed intense peak can be directly attributed to the interband recombination process of free carriers in the direct bandgap of p-GaAs, while the weak emission peaks at 473 nm and 540 nm correspond to 4F9/2-6H15/2 and 4F9/2-6H13/2 transitions, respectively. In the spectral region of 350 nm to 500 nm, the average thickness of the Dy2O3 layer was determined to be 11 nm. The electrical properties of the (Co/Au)/Dy2O3/p-porous GaAs metal–oxide–semiconductor (MOS) capacitor were investigated via capacitance–voltage (C–V) and conductance–voltage (G/ω–V) measurements in the temperature range of 100–400 K and frequency range of 50 Hz to 1 MHz, respectively. The experiments demonstrated that both capacitance and conductance were influenced by temperature and frequency. Additionally, the effect of temperature on interface state density (Nss) was studied, which showed that an increase in temperature led to a decrease in the interface state density (Nss) of the (Co/Au)/Dy2O3/p-porous GaAs (MOS) capacitor, as calculated by the Hill–Coleman method. The mean values of Nss for the (Co/Au)/Dy2O3/p-porous GaAs (MOS) capacitor were determined to be approximately 1012 eV−1 cm−2, making it suitable for electronic device applications. The lower values of Nss can be attributed to a low amount of local defect microstructure at the Dy2O3/p-porous GaAs interface due to the incorporation of the Dy2O3 layer into the porous GaAs. The electrical conductivity of the (Co/Au)/Dy2O3/p-porous GaAs (MOS) capacitor was studied using impedance spectroscopy in the frequency range from 50 Hz to 1 MHz at temperatures ranging from 80 K to 450 K. At low frequencies, the conductivity of alternating current (σAC) remained nearly constant, whereas at high frequencies, it increased rapidly, representing σDC and σAC, respectively. The Arrhenius plot of σAC shows two distinct slopes corresponding to two activation energies, 35 MeV and 10 MeV, in the chosen temperature range. [ABSTRACT FROM AUTHOR]

Lead halide perovskites are notorious for water-sensitivity and low hardness. Consequently, polishing CsPbBr3 crystals to achieve high-quality surfaces is challenging. We present a breakthrough mechanical polishing methodology tailored to the specific needs of these soft, moisture-sensitive semiconductors. Three-dimensional optical surface profiles over ~ 1 mm2 areas demonstrate high-quality surfaces with root-mean-square roughness values (< 10 nm) that are unparalleled for melt-grown CsPbBr3. We additionally delve into the polished wafers' fundamental optical constants and introduce an anti-reflection coating method, setting new standards for short-wave infrared transparency in CsPbBr3. These pivotal processing guidelines pave the way for advancing halide perovskite applications beyond academic curiosity. [ABSTRACT FROM AUTHOR]

This work uses pure polyvinyl chloride (PVC) with magnesium oxide (MgO) nanoparticles to enhance PVC's optical and shielding properties. The distribution of MgO nanoparticles in the PVC polymer was shown using a scanning electronic microscope, x‐ray diffraction, and Fourier transform infrared. The prepared samples' optical parameters and thermal analysis are investigated using ultraviolet (UV) spectroscopy and thermogravimetric analysis, respectively. The shielding characteristics parameters for the prepared samples were experimentally tested using a Cs‐137 point source with an energy of 0.662 MeV, and the outcomes were contrasted with what the XCOM software had calculated. Results indicated that optical constants were significantly affected by the addition of MgO wt% concentration. The linear attenuation coefficient was directly proportional to the weight concentration of MgO nanoparticle filler in the PVC matrix, and the ability to absorb UV increased. Adding MgO nanoparticle concentrations improved the PVC composite's radiation shielding behavior. It concluded that the PVC/MgO nanoparticle‐prepared samples are suitable for packaging for industrial applications and apron shielding for medical applications. [ABSTRACT FROM AUTHOR]

The complex dielectric permittivity of tungsten oxide at all stages of its colouration in a hydrogen-rich atmosphere was retrieved from measured VIS-NIR ellipsometric spectra of WO 3 /Pd bilayer. The retrieval was done by fitting the spectra with the Cody-Lorentz dispersion model, and, for optical absorption features, two Gaussian functions were added. The band gap edge, the Gaussian center energies, amplitudes, spectral widths and integrals were traced as the redox reaction progressed. Analysis of obtained data provides insight into mechanism of surface and bulk oxygen vacancies formation. We discuss these peculiarities in detail and show how they do affect the optical constants of WO 3 – x and potential sensors' response rates. • Ellipsometry for dielectric permittivity of WO 3 -x subjected to stepwise colouration in a hydrogen-rich atmosphere. • Absorption feature associated with WO 3 reduction was described by two competing processes fitted by Gaussians. • To elucidate the colouration mechanism, the Gaussians parameters were traced, illustrating oxygen vacancies formation. [ABSTRACT FROM AUTHOR]

A condensation reaction of salicylic acid with formaldehyde in the presence of sulfuric acid led to the synthesization of the bis(2-hydroxy-3-carboxyphenyl)methane (BHCM) ligand, which was subsequently allowed to bind with nickel (II) ions. In light of the information obtained from the elemental analyses (C, H, and M), spectral (IR, MS, 1H-NMR, and UV–Vis) and thermal and magnetic measurements, the most likely structures of the ligand and complex have been identified. It has been suggested that the BHCM coordinates in a tetradentate manner with two Ni(II) ions to produce an octahedral binuclear complex. The SEM and TEM morphology of the compounds showed spherical shapes. An X-ray diffraction analysis indicated a considerable difference in the diffraction patterns between BHCM (crystalline) and Ni–BHCM (amorphous), and the Scherrer equation was used to calculate the crystallite size. Some optical characteristics were estimated from UV–Vis spectra. The ligand and its nickel(II) complex underlie the range of semiconductors. It was verified that for human lung (A-549) cancer, the BHCM compound displayed a significant barrier to the proliferation test in noncancerous cells (human lung fibroblasts, WI-38), which was also undertaken. To demonstrate the binding affinities of the chosen compounds (BHCM and Ni–BHCM) in the receptor protein's active site [PDB ID: 5CAO], a molecular docking (MD) study was carried out. [ABSTRACT FROM AUTHOR]

Quaternary (AlxGa1−x)yIn1−yP alloys grown on GaAs substrates have recently gained considerable interest in photonics for improving visible light-emitting diodes, laser diodes, and photodetectors. With two degrees of freedom (x, y) and keeping growth on a lattice-matched GaAs substrate, the (AlxGa1−x)0.5In0.5P alloys are used for tuning structural, phonon, and optical characteristics in different energy regions from far-infrared (FIR) → near-infrared (NIR) → ultraviolet (UV). Despite the successful growth of (AlxGa1−x)0.5In0.5P/n+-GaAs epilayers, limited optical, phonon, and structural characteristics exist. Here, we report our results of carefully examined optical and vibrational properties on highly disordered alloys using temperature-dependent photoluminescence (TD-PL), Raman scattering spectroscopy (RSS), and Fourier-transform infrared reflectivity (FTIR). Macroscopic models were meticulously employed to analyze the TD-PL, RSS, and FTIR data of the (Al0.24Ga0.76)0.5In0.5P/n+-GaAs epilayers to comprehend the energy-dependent characteristics. The Raman scattering and FTIR results of phonons helped analyze the reflectivity spectra in the FIR region. Optical constants were carefully integrated in the transfer matrix method for evaluating the reflectivity R (E) and transmission T (E) spectra in the NIR → UV regions, validating the TD-PL measurements of bandgap energies (E g P L) . [ABSTRACT FROM AUTHOR]

Context and results: The structure, electronic and optical properties of single-layer transition metallic chalcogenides ZrX3 (X = S, Se, Te) have been studied by density functional theory. The electron energy dispersion curve shows that ZrX3 has semiconductor properties, in which the conduction band is mainly contributed by the correlated states of the Zr-d orbital, and the valence band is mainly contributed by the correlated states of the X-p orbital. It is found that b-axis and biaxial strain have great influence on the bandgap and the shift of density of states is also large. At the same time, the peak value of density of states increases greatly when biaxial strain is applied. It is of guiding significance for selecting suitable substrates to prepare two-dimensional ZrX3 materials to study their electronic properties. The calculation of optical constants confirms that ZrX3 has strong optical anisotropy. In the visible range, the light absorption efficiency of ZrX3 in the direction of electric field polarization [100] is higher than that in the direction of [010]. The reflectance spectral results show that ZrS3 and ZrSe3 in the [100] directions have the highest reflectance, and ZrTe3 in the [010] direction has the highest reflectance, even in the long electromagnetic radiation range (up to 10 eV), which is of great significance for the construction of visible optical devices. Computational method: All computations have been carried out based on density functional theory (DFT) as implemented in the CASTEP code. The pseudo-potential is adopted by the norm conserving, and the exchange correlation functional is adopted by the Perdew-Burke-Ernzerhof in local generalized gradient approximation (GGA). [ABSTRACT FROM AUTHOR]

This study aims to develop of silica (SiO2)/silicon nitride(Si3N4) nanomaterials doped polystyrene(PS) for use in a variety of electronics and optical nanodevices. By casting method, the films of (PS-SiO2-Si3N4) were coursed. The structure characteristics of (PS-SiO2- Si3N4)nanostructures were studied including optical microscopy(OM) and FTIR, and optical characteristics of (PS-SiO2-Si3N4) nanostructures also were studied. The OM confirmed that good distribution of (SiO2/Si3N4)NPs inside the matrix of PS and the FTIR indicates that there is a physical interaction between the polymer (PS) and (SiO2-Si3N4) NPs. The optical characteristics were measured at wavelengths ranging from 260 to 760 nm. The results showed when the ratio reached 6.9 wt% from the SiO2and Si3N4 NPs that the transmission(T) reduced while the absorption(A) increased, this capability qualifies it for use in a variety of optical fields. The energy gap(Eg) of PS when the SiO2 and Si3N4NPs content reached 6.9 wt% decreased, because of this behaviour, (PS-SiO2- Si3N4) nanostructures are regarded as crucial for optical and optoelectronic nanodevices. With increasing concentrations of SiO2 and Si3N4NPs, the optical constants, absorption coefficient, refractive index, extinction coefficient, real and imaginary dielectric constants, and optical conductivity rise. Lastly, the results confirmed the optical properties study that the (PS-SiO2-Si3N4) nanostructures might be used in a variety of nanoelectronics applications. [ABSTRACT FROM AUTHOR]