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ZnSe thin films were deposited on nonconducting glass substrates using different Zn2+ ion concentrations. The films were deposited at 80∘C for 2.0h via photo-assisted chemical bath technique and annealed for 2.0h at 250∘C. X-ray diffraction revealed a hexagonal structure with preferred orientation along the (002) plane and the average crystallite size decreased from 10.5nm to 6.8nm with increased Zn2+ ions. Raman spectra were used to confirm ZnSe phonon modes whose intensity increased with Zn2+ ion concentrations although with fluctuation. Optical analysis showed higher absorbance and low transmittance in the visible region than near infrared making the thin films good materials for selective absorber surfaces. The band gap increased from 2.52eV to 2.78eV as the Zn2+ ion concentration varied from 0.05% to 0.25%. The presence of the desired elements was confirmed by the EDS. Photoluminescence studies revealed three emission peaks which were all ascribed to defect state levels in ZnSe and all the samples emitted in reddish color according to CIE color chromaticity analysis. The selective absorption, wide band gap and broad emission properties suggest that the material is promising for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Preparing light‐diffusing material (LDM) combined with high haze and high transmittance has a significant value, but it is a challenge for the industry. The refractive index and diameter of light‐diffusing particles are the main factors. Two series of silicone microspheres with different diameters and refractive indices were prepared through precipitation polymerization and applied in LDM. The morphology of particles and LDM were investigated by scanning electron microscope. The corresponding thermal stability was studied by a thermal gravimetric analyzer. Furthermore, the influence of diameter and refractive index on light‐diffusing properties was explored systematically. The results show that the silicone particles have excellent thermal stability and can disperse evenly in a polycarbonate matrix. The corresponding LDM also has good thermal stability. It is the diameter, not the refractive index, acting as the key factor in preparing LDM combined with high haze and high transmittance. When achieving the same haze, selecting an appropriate diameter can prepare LDM with higher transmittance than other diameters. Different refractive indices lead to similar transmittance and haze of LDMs, but the refractive index can markedly affect the loading of particles to achieve an expected light‐diffusing property. This research has aspiring guidance for the industry. [ABSTRACT FROM AUTHOR]

The article investigates parameters that contribute to enhancing the rating in green building assessments focusing on occupant well-being efficiency and working leniency for environmental sustainability. The study assesses factors to green building including thermal transmittance, efficiency of indoor plumbing fixtures and fittings, waste reduction, energy efficient design and construction, indoor air quality and indoor artificial lighting.

Phase-pure crystalline cubic boron nitride (c-BN) thin films are of immense scientific and technical interest because of their suitable properties for optoelectronic and high-power applications, high thermal conductivity and hardness, chemical inertness to ferrous materials in high-temperature and caustic environments, and high optical transmittance over a broad wavelength range from the ultraviolet (UV) to the visible spectrum. However, the lack of controlled fabrication techniques for high-quality c-BN films significantly affects the reliable practical applications of this material. Recently, phase-pure single-crystal c-BN and a new phase of BN with unique properties, called quenched-BN (Q-BN), have been synthesized using a pulsed laser annealing (PLA) technique to overcome the current impediments in c-BN synthesis. This review paper comprehensively examines the current status of analytical research on the growth, characterization, and properties (optical and electrical) of c-BN films fabricated by different synthesis techniques, with a particular emphasis on the immensely promising PLA technique. In particular, the paper focuses on the processes used to obtain phase-pure c-BN films via epitaxial growth, characterization of defects and interfaces, and control of the structural, electrical, and optical properties of these films by controlling the growth parameters, including the laser–solid interaction for the direct conversion of nanocrystalline hexagonal boron nitride (h-BN) into crystalline c-BN using the PLA technique. The latest developments in c-BN electronics are also discussed, with a focus on producing p-and n-type conductivity using different dopants to achieve dopant concentrations far beyond the retrograde thermodynamic solid solubility limits. Finally, the future prospects and possible applications in emerging areas are discussed, as well as the goals and guidelines for future research of PLA-grown c-BN films. A comprehensive overview of the properties, application, characterization, shortcomings, and future prospects of c-BN [ABSTRACT FROM AUTHOR]

Laser polishing technique is one of the most effective post‐processing methods for 3D‐printed Polylactic acid (PLA) substrates and has gained significant interest of scientific research community in past few years. This paper aims to investigate the effect of fill density, laser power, and scanning speed on the polishing responses of 3D‐printed PLA substrates. These include surface roughness, mass ablation rate, and optical transmittance of PLA substrates printed using the fused deposition modeling technique. The optical transmittance was measured using Fourier‐transform infrared spectroscopy technique and surfaces were characterized using scanning electron microscope, and optical microscope. Minimum surface roughness of 1.04 μm was achieved at 5% laser power and 55% fill density constituting a decrease of 61.8% from unpolished PLA (2.735 μm). The lowest mass ablation rate (0.015 μg/pulse) was observed for the specimens with 40% infill density. Higher scanning speed enhanced the molecular bonding in PLA‐55 specimen indicated by increased peak transmittance ratios of CH bonds at stretching (1.021) and bending modes (1.045). [ABSTRACT FROM AUTHOR]

Photovoltaic technology offers a sustainable solution for the growing energy needs of the world, while reducing environmental impact. Transparent Conductive Oxides (TCOs), which are essential in photovoltaic technology, offer high light transmittance and effective charge carrier extraction. This research focuses on the impact of oxygen (O2) flow rates in the deposition of indium tin oxide (ITO) films on n-type crystalline silicon (c-Si) substrates by DC magnetron sputtering. The structural, optical, and electrical properties were analyzed. Based on the results, the optimal O2 ratio was determined and used in the fabrication of SHJ solar cells, achieving an efficiency of 18.6%. [ABSTRACT FROM AUTHOR]

The phenomenon of a target echo peak overlapping with the backscattered echo peak significantly undermines the detection range and precision of underwater laser fuzes. To overcome this issue, we propose a four-quadrant dual-beam circumferential scanning laser fuze to distinguish various interference signals and provide more real-time data for the backscatter filtering algorithm. This enhances the algorithm loading capability of the fuze. In order to address the problem of insufficient filtering capacity in existing linear backscatter filtering algorithms, we develop a nonlinear backscattering adaptive filter based on the spline adaptive filter least mean square (SAF-LMS) algorithm. We also designed an algorithm pause module to retain the original trend of the target echo peak, improving the time discrimination accuracy and anti-interference capability of the fuze. Finally, experiments are conducted with varying signal-to-noise ratios of the original underwater target echo signals. The experimental results show that the average signal-to-noise ratio before and after filtering can be improved by more than 31 dB, with an increase of up to 76% in extreme detection distance. [ABSTRACT FROM AUTHOR]

To make the colorless polyimides (CPIs) suitable for the application of flexible display technology, the polyimide (PI) films need to have both good optical properties and thermal properties. To get the wanted properties, 2‐(2‐methyl‐4‐(2‐methyl‐4‐aminobenzamido)phenyl)‐5‐(2‐methyl‐4‐aminobenzamido)‐N‐phenylbenzimidazol (5a) and 2‐(2‐methyl‐4‐(2‐trifluoromethyl‐4‐aminobenzamido)phenyl)‐5‐(2‐trifluoromethyl‐4‐aminobenzamido)‐N‐phenylbenzimidazol (5b) were synthesized, which both contained benzimidazole and bis‐amide structures. Two kinds of PI films were polymerized with cyclobutane‐1,2,3,4‐tetracarboxylic dianhydride (CBDA). With the contribution of side groups (CH3 or CF3), the resulting PI films presented relatively superior optical properties (transmittance at 400 nm was 59% and 68% respectively) and low coefficient of thermal expansion (CTE = 22 and 25 ppm K−1). These good properties suggest that these PI films have the potential for flexible display usage. [ABSTRACT FROM AUTHOR]

ZnAlO thin films with different Al concentrations were prepared on glass and silicon substrates by Magnetron sputtering in this paper. Scanning electron microscopy (SEM), X-ray diffraction (XRD), spectrometer and other instruments were used to analyze the surface morphology, microstructure, transmittance and Raman spectrum of the films. The results showed that trace Al doping significantly increased the surface morphology and size of ZnAlO thin films; The low doped ZnAlO thin film exhibits a good preferred orientation. As the Al doping concentration increases, the main growth direction of the crystal gradually shifts from (101) to (103), and the grain size decreases with the increase of doping concentration during low doping; When the wavelength of ZnAlO film is less than 330 nm, the transmittance of the film is almost zero; When the wavelength is greater than 350 nm, the transmittance of the thin film decreases with the increase of Al doping concentration, and there is a blue shift trend with the increase of Al concentration. When the wavelength is between 420-900nm, the average transmittance of ZnAlO thin film can reach over 90%, and the transmission performance is good; The ZnAlO thin films all have structural characteristic peaks of wurtzite with a frequency of about 437 cm−1, and the Raman peak position does not move with the increase of Al concentration. [ABSTRACT FROM AUTHOR]

A long‐standing challenge in volume visualization is the effective communication of relevant spatial structures that might be hidden due to occlusions. Given a scalar field that indicates the importance of every point in the domain, previous work synthesized volume visualizations by weighted averaging of samples along view rays or by optimizing a spatially‐varying extinction field through an energy minimization. This energy minimization, however, did not directly measure the contribution of an individual sample to the final pixel color. In this paper, we measure the visibility of relevant structures directly by incorporating the transmittance into a non‐linear energy minimization. For the first time, we not only perform a transmittance‐based extinction optimization, we concurrently optimize the camera position to find ideal viewpoints. We derive the partial derivatives for the gradient‐based optimization symbolically, which makes the application of automatic differentiation methods unnecessary. The transmittance‐based formulation gives a direct visibility measure that is communicated to the user in order to make aware of potentially overlooked relevant structures. Our approach is compatible with any measure of importance and its versatility is demonstrated in multiple data sets. [ABSTRACT FROM AUTHOR]

When light propagates in a scattering medium such as haze, it is partially scattered and absorbed, resulting in a decrease in the intensity of the light emitted by the imaging target and an increase in the intensity of the scattered light. This phenomenon leads to a significant reduction in the quality of images taken in hazy environments. To describe the physical process of image degradation in haze, the atmospheric scattering model is proposed. However, the accuracy of the model applied to the usual fog image restoration is affected by many factors. In general, fog images, atmospheric light, and haze transmittances vary spatially, which makes it difficult to calculate the influence of the accuracy of parameters in the model on the recovery accuracy. In this paper, the atmospheric scattering model was applied to the restoration of hazed images with a single transmittance. We acquired hazed images with a single transmittance from 0.05 to 1 using indoor experiments. The dehazing stability of the atmospheric scattering model was investigated by adjusting the atmospheric light and transmittance parameters. For each transmittance, the relative recovery accuracy of atmospheric light and transmittance were calculated when they deviated from the optimal value of 0.1, respectively. The maximum parameter estimation deviations allowed us to obtain the best recovery accuracies of 90%, 80%, and 70%. [ABSTRACT FROM AUTHOR]

With the rapid development of emerging photovoltaics technology in recent years, the application of building-integrated photovoltaics (BIPVs) has attracted the research interest of photovoltaic communities. To meet the practical application requirements of BIPVs, in addition to the evaluation indicator of power conversion efficiency (PCE), other key performance indicators such as heat-insulating ability, average visible light transmittance (AVT), color properties, and integrability are equally important. The traditional Si-based photovoltaic technology is typically limited by its opaque properties for application scenarios where transparency is required. The emerging PV technologies, such as organic and perovskite photovoltaics are promising candidates for BIPV applications, owing to their advantages such as high PCE, high AVT, and tunable properties. At present, the PCE of semitransparent perovskite solar cells (ST-PSCs) has attained 14% with AVT of 22-25%; for semitransparent organic solar cells (ST-OSCs), the PCE reached 13% with AVT of almost 40%. In this review article, we summarize recent advances in material selection, optical engineering, and device architecture design for high-performance semitransparent emerging PV devices, and discuss the application of optical modeling, as well as the challenges of commercializing these semitransparent solar cells for building-integrated applications. [ABSTRACT FROM AUTHOR]

Polyvinyl chloride (PVC)/polyethylene oxide (PEO)/x wt % polyaniline (PANI) polymer blends were produced using a solvent casting method. X-ray diffraction was used to investigate the formed blends. The effect of adding different amounts of PANI on the light absorbance, transmittance, reflectance, extinction coefficient, refractive index, optical dielectric properties, nonlinear optical parameters and relaxation time characteristics of the PVC/PEO blends were explored. The direct and indirect optical band gap energies of the undoped PVC/PEO were 4.25 and (4.06, 2.76) eV, respectively. The direct and indirect optical band gap energies were reduced to their lowest values (4.02, 3.1) and (3.68, 2.14, 1.12) eV as the amounts of PANI were increased to 0.2 wt %. The effect of alloying between PVC and PEO and adding PANI on the emitted fluorescence spectra under various excitation wavelengths were investigated. All samples displayed varying degrees of blue-violet, blue, or blue-green colors depending on the concentrations of PANI. [ABSTRACT FROM AUTHOR]

In order to develop optical films that can be applied to window films and high-brightness films, self-produced A masterbatch, B masterbatch and film-grade polyester were used to prepare biaxially oriented polyester (BOPET) films by extrusion casting machine and tensile test machine. The microstructure, roughness, optical properties, friction coefficient and mechanical properties of BOPET films were studied by polarizing microscope, line roughness meter, non-contact 3D surface profiler, transmission fog shadowgraph, gloss meter, friction coefficient meter and material tensile machine. The results show that the opening agent is a spherical structure, the size is in the submicron level, showing a monodisperse state. When the content of the opening agent (B masterbatch) is 0.012 5%, the roughness of the film surface Ra≤23 μm, Sa≤17 μm, haze, transmittance, clarity, gloss can reach 0.88%, 90.8%, 99.6% and 136 GU, respectively. The static friction coefficient/dynamic friction coefficient is 0.36/0.30. The anti-bonding effect is good and the mechanical properties are excellent. The prepared BOPET film is a kind of low fog and high definition BOPET film with good comprehensive properties. [ABSTRACT FROM AUTHOR]

Cubic ZrV 2 O 7 thin films have been synthesized by sol-gel spin-coating method. The influences of annealing temperatures on the phase composition and morphology of ZrV 2 O 7 thin films were investigated using XRD, SEM, and EDX. Negative thermal expansion (NTE) and optical performances of cubic ZrV 2 O 7 thin films were analyzed using variable temperature XRD and UV–Vis spectroscopy. Results indicate that as-deposited ZrV 2 O 7 thin films have an amorphous structure with smooth and dense surface. Cubic ZrV 2 O 7 thin films were prepared after heat treatment at 720 °C for 1 h. It was found that the thin films contained V 2 O 5 impurity with the Zr: V = 1:2 precursor solution. Pure cubic ZrV 2 O 7 thin films were fabricated with the Zr: V = 1.75:2 precursor solution. Cubic ZrV 2 O 7 thin films show isotropic NTE in the temperature range of 100–700 °C. The coefficients of thermal expansion (CTEs) of ZrV 2 O 7 films along the a , b , and c axes are −6.88 × 10−6 °C−1, and the volumetric and linear CTEs are −20.56 × 10−6 °C−1 and -6.85 × 10−6 °C−1, respectively. The transmittance of cubic ZrV 2 O 7 thin film is approximately 80 %. [ABSTRACT FROM AUTHOR]

This work reports the modification in the homogeneity of ablation effects with the assistance of nonlinear optical phenomena exhibited by C. albicans ATCC 10231, forming a biofilm. Equivalent optical energies with different levels of intensity were irradiated in comparative samples, and significant changes were observed. Nanosecond pulses provided by an Nd:YAG laser system at a 532 nm wavelength in a single-beam experiment were employed to explore the photodamage and the nonlinear optical transmittance. A nonlinear optical absorption coefficient −2 × 10−6 cm/W was measured in the samples studied. It is reported that multiphotonic interactions can promote more symmetric optical damage derived by faster changes in the evolution of fractional photoenergy transference. The electrochemical response of the sample was studied to further investigate the electronic dynamics dependent on electrical frequency, and an electro-capacitive behavior in the sample was identified. Fractional differential calculations were proposed to describe the thermal transport induced by nanosecond pulses in the fungi media. These results highlight the nonlinear optical effects to be considered as a base for developing photothermally activated phototechnology and high-precision photodamage in biological systems. [ABSTRACT FROM AUTHOR]

Terahertz frequency domain spectroscopy provides a superior resolution in the broad range from 50 GHz to 5 THz. However, temporal frequency drift and the standing wave pattern in the spectrometer, which often act simultaneously, produce intensive coherent noise in the transmittance spectra of the measured samples. The paper presents a spectrum processing method allowing to reduce the coherent noise and thus significantly enhance the accuracy of spectral data analysis. The idea of the method is to remove the small-period (0.25 GHz) oscillations in the standing wave pattern of the measured signal by applying the windowed Fourier filtering. The large-period (4 GHz) oscillations in the measured spectra are broadened and then used to compensate the frequency drift of the two consecutive measurements of the signal with the sample and without it. The proposed approach is tested on the measured spectra of metamaterial and silicon wafer. Its advantage over the classical method based on the averaging of adjacent data points is confirmed. Our work benefits to optimization of the frequency domain terahertz systems and paves the way for fast and accurate analysis of spectral data. [ABSTRACT FROM AUTHOR]

The present investigation focused on the effect of boron nitride quantum dots (BNQDs) as a filler on the optical properties of polyvinyl butyral (PVB) nanocomposites. Herein, polymer nanocomposite films with advanced UV protection and high photoluminescence properties were successfully synthesized. Polymer nanocomposite films were produced by adding BNQDs to the polymer in different ratios by a simple solution forming and casting method. The films were decomposed at different UV degradation times, and their UV protective properties were tested. The structural, morphological, optical and chemical interaction of BNQDs/PVB nanocomposites was confirmed by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Fourier Transform Infrared (FTIR), micro‐Raman spectroscopy, ultraviolet and visible (UV–Vis), and photoluminescence (PL) analyzes. As the amount of BNQDs in the polymer increased, the intensity of the bright images separated from the polymer also increased. TEM images confirmed the good distribution of quantum dots in PVB polymer matrix. Polymer composites doped with 0.25% and 0.4% BNQDs show excellent UV‐shielding properties as the transmittance in the UV region decreased about 69% and 95%, respectively. As the addition of BNQDs into the polymer increased, the PL emission of the pure PVB film, which showed almost no emission, increased significantly. [ABSTRACT FROM AUTHOR]

The 2,4,5-Triphenyl Imidazole (TPI) C21H16N2 samples were deposited as thin film by means of the physical vapor deposition (PVD) on glass and silicon substrates. As well as, three solutions with different concentrations using dimethyl sulfoxide (DMSO) solvent. The physical properties of all samples were investigated using different techniques. The thin film's morphology was examined using atomic force microscopy (AFM) of the sample on silicon substrates, revealing a highly rough surface. The optical characteristics of both the thin film on glass substrate, the solutions, and the powder were studied through transmittance and absorbance measurements, which helped determine a value of the band gap of 3.45 eV. Photoluminescence and thermal photoluminescence spectroscopy showed the high emission of the material in its different aspects. Theoretical simulations of the HOMO–LUMO gap and electronic absorption spectra were obtained using the density functional theory (DFT) approach. [ABSTRACT FROM AUTHOR]

Herein, we report significant microstructure-induced dynamic visible–infrared transmittance regulation on a novel fluoroaluminate glass (AlF 3) via femtosecond-laser-customized fabrication technology. Fluoroaluminate glass, which has excellent optical transmittance in the visible–infrared wavelength range (400–5000 nm), is a candidate for visible and infrared optical devices. Based on its performance, three types of microstructures or material transitions (Snow-Layer Microstructure (SLS), Surface-Ablation Microstructure (SAS), and Interior-Modified Microstructure (IMS)) were successfully achieved using a femtosecond-laser-customized microstructure, including surface and interior fabrication routes with cylindrical lens focusing. Dynamic and reversible structural transition features were observed between the snow-layer and surface-ablation microstructures. These types of structures showed different transmittance regulation trends at visible and infrared wavelengths. The transmittance is decreased for IMS, SAS, and SLS in the visible region, while in the infrared region the transmittance increased for IMS and decreased for SAS and SLS. Based on Raman spectroscopy analyses, the chemical structures of the SAS before and after femtosecond-laser ablation appeared to remain constant, whereas the SLS showed a significant difference, giving rise to different transmittance regulations. This study provides a novel fabrication method and strategy for regulating visible and infrared transmission and promotes smart application of glass materials. [ABSTRACT FROM AUTHOR]

The light transmittance measurement method, which is used to characterize smoke characteristic signal of solid rocket motor plume, can provide important reference for development and design of low smoke characteristic signal solid propellants and motors. The light transmittance measurement method of solid rocket motor plume based on laser modulation spectrum analysis is proposed in this paper. By using a 405 nm laser as the light source and a narrow‐band filter detection method, the influence of plume radiation on the measurement of light transmittance of solid rocket motor plume smoke can be minimized. Additionally, combined with the laser modulation spectrum analysis technology, the signal amplitude is selected by the laser modulation frequency to improve the signal‐to‐noise ratio of the signal. Compared with the laser constant current measuring mode, laser high‐frequency modulation measuring mode with spectrum analysis effectively improves the optical transmittance measurement accuracy. Based on this, a solid rocket motor plume smoke transmittance test system is developed to measure the plume smoke of standard test motors with different propellants and combustion chamber pressures. The results demonstrate that the system can effectively measure the light transmittance of the plume smoke. The light transmittance of solid rocket motor plume can be increased by reducing the aluminum content of solid propellant or increasing the pressure of the combustion chamber. Thus, this research provides an effective measuring tool for evaluating smoke concentration of solid rocket motor plume, which is beneficial to develop low smoke characteristic signal solid propellants and motors. [ABSTRACT FROM AUTHOR]

Thermal considerations affect the performance of most microsystems. Although surface techniques can give information on the thermal properties within the material or about buried heat sources and defects, mapping temperature and thermal properties in three dimension (3D) is critical and has not been addressed yet. Infrared thermography, commonly used for opaque materials, is not adapted to semi-transparent samples such as microfluidic chips or semiconductor materials in the infrared range. This work aims at answering these needs by using the variations of transmittance with temperature to obtain information on the temperature within the thickness of the sample. We use a tunable mid-infrared light source combined with an infrared camera to measure these variations of transmittance in a glass wafer. We couple this technique with a thermal model to extract the thermotransmittance coefficient—the coefficient of temperature variation of the transmittance. We then introduce a semiempirical model based on Lorentz oscillators to estimate the temperature-dependent optical properties of our sample in the mid-IR spectral range. Combined with the measurement, this paper reports the spectroscopic behavior of the thermotransmittance coefficient in the mid-IR range and a way to predict it. [ABSTRACT FROM AUTHOR]

Context: To find the potential value of Ca3N2 in the field of optoelectronics, the physical properties of Ca3N2 will be analyzed. It can be concluded from the electronic properties that the Ca-N bonds of α-Ca3N2 are more stable than those of δ-Ca3N2 and ε-Ca3N2. The dielectric function, reflectivity function, and absorption function of three types of Ca3N2 were accurately calculated, and it was concluded that α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 have greater transmittance for visible light and exhibit optical transparency in the near-infrared frequency domain. Combined with the high hardness, strong bonding, high melting point, and wear resistance of Ca3N2, Ca3N2 can be used as a new generation of window heat-resistant materials. The α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 are indirect, direct, and indirect narrow bandgap compounds, respectively, that is, δ-Ca3N2 is more suitable for luminescent materials than α-Ca3N2 and ε-Ca3N2. α-Ca3N2 and δ-Ca3N2 have high reflective properties in the ultraviolet region and can be used as UV protective coatings. All three Ca3N2 materials can be used industrially to synthesize photovoltaic devices that operate in the ultraviolet region. Methods: Based on the first-principles of density functional theory calculations, the structures, electronic properties, and optical properties of α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 were calculated. The calculation results show that although the α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 have similar electronic structures, some phases have better properties in some aspects. [ABSTRACT FROM AUTHOR]

In this investigation, a nanostructured Cu2O thin film absorber layer is electrodeposited, exploring the impact of varying negative applied voltages and deposition time. Notably, the Cu2O thin film demonstrated optimal absorbance at −0.95 V, contrasting sharply with a minimum at −0.97 V. The authors' findings underscore that the peak absorbance was achieved at −0.95 V, coinciding with the lowest transmittance observed after 80 min of deposition, aligning with a maximal absorption coefficient of 21 × 103 cm−1. At a deposition time of 5 min, the Cu2O thin film exhibited a noteworthy maximum Urbach energy of 2.00 eV and a minimum steepness parameter of 0.013. In contrast, the lowest Urbach energy was recorded at 0.34 eV, with the highest steepness parameter occurring at an applied voltage of 0.93 V. Furthermore, this study revealed a gradual increase in the refractive index with higher applied voltages, reaching its pinnacle at −1.5 V. These results collectively emphasize the nuanced interplay between applied voltage, deposition time and the optical properties of the nanostructured Cu2O thin film. The observed trends hold significant implications for optimizing the performance of thin film absorber layers, particularly in the context of enhancing absorbance and tailoring optical characteristics for specific applications. [ABSTRACT FROM AUTHOR]

The growth system has been upgraded, technological growth parameters have been optimized, and a high-quality crystal has been grown from the LiNb0.95Ta0.05O3 charge. Spectral dependences of the transmittance of a sample cut from this crystal have been measured before and after the transition to the single-domain state in the range of 300–700 nm with allowance for anisotropy and dichroism. Spectral dependences of the absorption coefficient α(λ) and degree of dichroism Δ(λ) have been obtained. The dependences α(λ) contain an absorption band at λ ~ 480 nm, regardless of the light propagation direction. When light propagates perpendicular to the optical axis, absorption bands at λ ~ 560, 608, 620, and 656 nm can additionally be observed. The transition to the single-domain state leads to sample bleaching. The dependences Δ(λ) for the X and Y cuts are characterized by identical extrema, whose positions correspond to the absorption bands in the dependences α(λ); additional extrema manifest themselves at λ ~ 400 and 445 nm. When light propagates along the optical axis, the dependences Δ(λ) are nonzero; they are characterized by much smaller values (in comparison with the directions perpendicular to the optical axis) and have extrema at λ ~ 440, 560, 600, 620, and 640 nm. [ABSTRACT FROM AUTHOR]

The growth system has been upgraded, technological growth parameters have been optimized, and a high-quality crystal has been grown from the LiNb0.95Ta0.05O3 charge. Spectral dependences of the transmittance of a sample cut from this crystal have been measured before and after the transition to the single-domain state in the range of 300–700 nm with allowance for anisotropy and dichroism. Spectral dependences of the absorption coefficient α(λ) and degree of dichroism Δ(λ) have been obtained. The dependences α(λ) contain an absorption band at λ ~ 480 nm, regardless of the light propagation direction. When light propagates perpendicular to the optical axis, absorption bands at λ ~ 560, 608, 620, and 656 nm can additionally be observed. The transition to the single-domain state leads to sample bleaching. The dependences Δ(λ) for the X and Y cuts are characterized by identical extrema, whose positions correspond to the absorption bands in the dependences α(λ); additional extrema manifest themselves at λ ~ 400 and 445 nm. When light propagates along the optical axis, the dependences Δ(λ) are nonzero; they are characterized by much smaller values (in comparison with the directions perpendicular to the optical axis) and have extrema at λ ~ 440, 560, 600, 620, and 640 nm. [ABSTRACT FROM AUTHOR]

Molybdenum ditelluride (MoTe2), a member of the transition metal dichalcogenide family, holds significant promise in optoelectronic applications. To harness its full potential, it is imperative to understand its fundamental optical properties, including refractive indices. Herein, measurements of the transmittance and reflectance spectra of thin MoTe2 layers are conducted featuring hexagonal and monoclinic structures across the far‐infrared (IR) and mid‐IR spectral regions. These spectra are fitted, allowing to extract the complex refractive index and optical conductance. In the semiconducting hexagonal phase, both the conductance and extinction coefficient remain negligible below 3000 cm−1 and increase at higher energies. Conversely, the monoclinic phase exhibits a conductance peak in the far‐IR region and a continuous increase from 1000 to 6000 cm−1. The findings are compared with existing theoretical and experimental results to provide further insights into MoTe2's optical behavior. [ABSTRACT FROM AUTHOR]

Surface reflectance measurement is an integral part of the vicarious calibration of satellite sensors and the validation of satellite-derived top-of-atmosphere (TOA) and surface reflectance products. A well-known practice for estimating surface reflectance is to conduct a field campaign with a spectrometer and a calibration panel, which is labor-intensive and expensive. To address this issue, the Radiometric Calibration Network, RadCalNet, has been developed, which automatically collects surface reflectance over several selected sites. Neither of these approaches can continuously track the atmosphere, which limits their ability to compensate for atmospheric transmittance change during target measurement. This paper presents the dual-spectrometer approach that uses a stationary spectrometer dedicated to continuously tracking changes in atmospheric transmittance by staring at a calibrated reference panel while the mobile spectrometer measures the target. Simultaneous measurement of the reflectance panel and target help to transfer calibration from the stationary spectrometer to the mobile spectrometer and synchronize the measurements. In this manner, atmospheric transmittance changes during target measurement can be tracked and used to reduce the variability of the target surface reflectance. This paper uses field measurement data from combined field campaigns between different calibration groups at Brookings, South Dakota, and Landsat 8 and Landsat 9 underfly efforts over Coconino National Forest, Arizona, and Guymon, Oklahoma. Preliminary results show that even in a clear sky condition, where atmospheric transmittance changes are minimal, the precision of target surface reflectance estimated using the dual-spectrometer approach is 2–6% better than the single-spectrometer approach. The dual-spectrometer approach shows the potential for a substantial improvement in the precision of the target spectral profile when the atmospheric transmittance is changing rapidly during field measurement. Results show that during non-optimal atmospheric conditions, the dual-spectrometer approach improved the precision of the surface reflectance by 50–60% compared to the single-spectrometer approach across most spectral regions. The ability to estimate surface reflectance more precisely using the dual-spectrometer approach in different atmospheric conditions improves the vicarious calibration of optical satellite sensors and the validation of both TOA and surface reflectance products. [ABSTRACT FROM AUTHOR]

CsLiB6O10 (CLBO) is a high-performance nonlinear optical crystal, particularly suitable for high-power ultraviolet laser by fourth harmonic generation (FHG, 266 nm) and fifth harmonic generation (FIHG, 210 nm). A CLBO crystal with the size of 120 mm x 112 mm x 62 mm was successfully grown using top seeded solution growth (TSSG) method in this work. The grown CLBO crystal exhibits a complete appearance without macroscopic defects such as cracking and visible scattering particles. A CLBO FIHG crystal component was cut from this crystal, and its UV-visible-near infrared transmittance, optical uniformity and weak absorption properties were analyzed in detail. The results include that, the mean transmittance exceeds 90% from 210 nm to 1 800 nm, optical uniformity result is 3.8 x 10-5 and the weak absorption is 90 x 10-6cm-1 at 1 064 nm. All of these results indicate that the as-grown CLBO crystal possesses good transmittance in the ultraviolet region, high optical uniformity and low weak absorption, laying the foundation for subsequent research on related applications. [ABSTRACT FROM AUTHOR]

A novel method has been proposed to induce rapid upward movement of colloidal particles with a density lower than water by applying an electric field of several V/mm in water. This phenomenon, known as the Electrically Induced Rapid Sedimentation (ERS) effect, marks the first occurrence of 'rapid upward movement of colloidal particles' within the scope of this phenomenon. Focusing on hollow particles, an investigation of the ERS effect was conducted through transmittance measurement. The hollow particles in water showed a drastic increase in ascending velocity through the application of an electric field. The ascending velocity raised when increasing the electric field strength. Utilizing a quasi-DC electric field (an extremely low-frequency AC electric field), aggregate structures were captured for the first time. [ABSTRACT FROM AUTHOR]

Glass ceramic (GC) is a promising optical gain material for fiber laser applications. However, the greatest challenge for GC is the conflict between high crystallinity and significant optical loss produced by crystals scattering. Herein, we propose a simple method based on crystal engineering of glass to enhance the crystallinity and transmittance. On the basis of this approach, the crystallinity, transparency and luminescence efficiency of the GC samples are all enhanced dramatically. In addition, owing to the depletion of Y3+ ions in the glass matrix during the precipitation of KYF 4 crystals, the refractive index differences between the glass matrix and the crystals are significantly diminished, which results in suppressed light scattering towards higher crystallinity (∼72%) and transmittance (∼88% at 900 nm). These excellent performances of GC show that crystal engineering of glass not only presents a way to overcome the conflict between crystallinity and transmittance, but also offers significant potential for the fabrication of optical composites with multiple functions. [ABSTRACT FROM AUTHOR]

The Kirigami technique has recently inspired the design of reconfigurable electromagnetic metamaterials that can be easily realized by embedding a patterned cutting array into a supportive substrate. However, these existing designs mainly focus on the 2D‐to‐3D transformable morphology that induces the modulation of the spectral responses. This work proposes a kirigami‐based planar reconfiguration mechanism and extends advanced applications in the dynamic near‐field imaging and tunable double‐foci metalens. These extraordinary tunabilities originate from three meta‐atoms that can be mutually transformed into the morphologies with non‐chirality and opposite chirality under the tensile strain. By utilizing the transmittance characteristics of reconfigurable meta‐atoms, the metamaterial is constructed to achieve three‐foldable near‐field displays and a longitudinal double‐foci metalens empowered with tunable focusing length and intensity ratio. Two anisotropic chiral meta‐atoms in deformed states that possess overwhelming transmittance difference of circularly cross‐polarized components to magnify the focusing intensity ratio of two foci for the proposed metalens are further proposed. The exhibited observations provide typical examples of a wide spectrum of applications of the kirigami‐based reconfiguration mechanism, and it may pave the avenue to spark manifold functional devices for applicable electromagnetic manipulations such as multifunctional hologram display, dynamic beam shaping, and steering, as well as the conformal design of meta‐devices. [ABSTRACT FROM AUTHOR]

The occurrence of optical loss on the surface of solar cells is inevitable due to the difference in the refractive index between air and glass, as well as the insufficient absorption of the active layer. To address this challenge, micron-sized geometry arrays, such as hemispheres and hemisphere pits, are prepared on quartz glass through the advanced indirect patterning technology of UV-LIGA. These geometric arrays exhibit multiple mechanisms for controlling light waves, including multiple rebounds, diffraction scattering, and total internal reflection. These synergistic effects suppress optical losses at the device's surface and prolong the photon propagation path in the active layer. After being patterned with this structure, the average transmittance and haze of the quartz glass reach 93.91% and 75%, respectively. Compared to their flat counterpart, the decorated monocrystalline silicon solar cells demonstrated an apparent improvement in photocurrent and produced a 7.2% enhancement in power conversion efficiency. [ABSTRACT FROM AUTHOR]

Antimonous oxide (Sb2O3) has intriguing physical and chemical features that make it useful in various device applications, including solar cells. Nanofilms of Sb2O3:0.02 wt.% CuO were prepared onto glass and silicon substrates etched by laser using a thermal evaporation process in a vacuum, with different thicknesses of about 20, 30, and 40 nm. The deposited nanofilms have no distinguishing peaks in XRD analysis. The broadening of peak shows due to the absence of long-range symmetry; as a result, the nanocrystalline structure is disorganized. Scanning electron microscope analysis of the surface morphology of the formed nanofilms showed to be spread out uniformly and were devoid of islands and voids. The particles were all about the same size, and the new structures were created with a thickness of 40 nm. Atomic force microscopy scanning images showed the nanofilms' homogeneous surface morphology with granular shape. As nanofilm thickness increased, so did average roughness, root mean square value, and grain diameter. Optical characteristics revealed a reduction in the transmittance spectrum with increasing thicknesses. Instead, the optical energy gap ( E g o p t ) was decreased by quantum confinement from 3.56 to 3.48 eV. The electrical properties of the nanofilms were analyzed, and it was found that all were n-type and that mobility (µ) decreased with nanofilm thickness. As shown by the I–V characteristics, the solar cell's conversion efficiency increases to 6.373% at power = 100 mW/cm2 with 0.138 filling factor, 4 V of open circuit voltage, and 2.6 mA of short circuit. [ABSTRACT FROM AUTHOR]

The residual resources of ramie fiber-based textile products were used as raw materials. Ramie fiber felt (RF) was modified by NaClO2 aqueous solution and then impregnated with water-based epoxy resin (WER). RF/WER transparent composite materials were prepared by lamination hot pressing process. The composite materials' color difference, transmittance, haze, density, water absorption, and mechanical properties were determined to assess the effects of NaClO2 treatment and the number of ramie fiber layers on the properties of the prepared composites. The results showed significantly improved optical and mechanical properties of the RF/WER transparent composites after NaClO2 treatment. With the increase of ramie fiber layers, the composites' whiteness, transmittance, and water absorption decreased while the haze increased. For material with three layers, the optical transmittance in the visible light region was 82%, and the haze was 96%, indicating the material has both high transmittance and high haze characteristics. The tensile strength increases with the increase of the number of layers, and the tensile strength of the composite with six layers is 243 MPa. This study broadens the scope of application of ramie fiber as a new option for home decoration materials. [ABSTRACT FROM AUTHOR]

In this work, we explore a new experimental study of Barium oxide (BaO) thin films, fabricated using the physical vapor deposition (PVD) technique on both glass and silicon substrates. The BaO thin films have emerged as highly adaptable materials with immense potential across multiple technological domains. The investigation focuses on the morphological, optical, and electrical properties of BaO thin films to determine their potential for various applications. These films, consistently tailored to a thickness of 100 nm, exhibit exceptional optical properties, boasting an impressive transmittance rate of up to 90%. This makes them exceptionally well-suited for applications that demand superior optical transmission, such as flat-panel displays, photovoltaic devices, and various optoelectronic applications. The films' low roughness values, measured at 6.31 nm for glass-deposited films and 13.32 nm for silicone-deposited ones, underscore their uniformity, ensuring stable and precise performance control in diverse applications. Further underscoring their versatility is the wide energy gap of 2.93 eV, suggesting their potential utility in advanced optoelectronic devices that require higher energy levels. In addition to their optical prowess, BaO thin films exhibit impressive electrical resistance, measuring at 3.3 × 108 ohms, rendering them promising candidates for specialized applications, including pressure and humidity sensors, as well as electrical insulation devices. Overall, these films represent an exciting avenue for addressing specific technological needs and driving innovation in the realm of thin film technology. [ABSTRACT FROM AUTHOR]

Microstructure and composition significantly influence the physical properties of thin films. Therefore, these can be adapted to enhance the functionality of thin films for practical applications. Herein, the anomalous microstructural evolution of sputtered GeO2 thin films based on postdepositional heat treatments is reported. Temperature‐dependent microstructural variations are investigated systematically via a combinatorial postdepositional heat treatment employing a natural thermal gradient in a tube furnace. Heat treatment under an oxidizing atmosphere results in a transition from the amorphous phase to the quartz phase, and subsequent heat treatments under a reducing atmosphere cause H2O‐incorporated chemical reactions. Hence, these conditions create unique microstructural features and yield optical transmittance variations in the GeO2 thin films. The phase transition induces the formation of spherulitic hexagonal GeO2 crystallites, and further increase in the temperature promotes the agglomeration of crystallites in the amorphous matrix. The incorporation of H2O results in the growth of the microstructure, and the chemical reduction to Ge metal begins to generate small granules from the boundary of the microstructures. The experimental results and proposed mechanisms presented herein for the microstructural and compositional changes serve as references for designing the physical properties of thin films. [ABSTRACT FROM AUTHOR]

DNA-driven self-assembly enables precise positioning of the colloidal nanoparticles owing to specific Watson–Crick interactions. Another important feature of this self-assembly method is its reversibility by controlling the temperature of the medium. In this work, we study the potential of another mechanism to control the binding/unbinding process of DNA-functionalized gold nanoparticles. We employ laser radiation that can be absorbed by the gold nanoparticles to heat their network and disassociate it. Here, we show that we can actively control the optical properties of the nanoparticle network by external optical excitation. We find out that by irradiating the structure with a green hand-held laser, the total transmittance can increase by ∼30% compared to the transmittance of the sample not irradiated by the laser. Similarly, the optical microscopy images indicate the transformation of the nanoparticle network from opaque to transparent, while the nanoparticles formed a network again after the laser irradiation stopped. Our results prove that the optical excitation can be used to tailor the structure and thus the optical properties of the DNA-self-assembled nanoparticle networks. [ABSTRACT FROM AUTHOR]

High-resolution remote sensing image defogging can bring a lot of convenience to downstream image tasks, however, existing remote sensing image defogging algorithms have many drawbacks. In this paper, an O-type network structure for remote sensing image defogging is proposed. On the one hand, a flipped inverted attention residual block is designed to solve the shortcomings of information loss and gradient explosion of the basic residual block, so that the network can fuse features in multiple scales and directions to provide more detailed edge information and texture information for the decoding stage. On the other hand, a multi-loss function constraint network is designed to improve the shortcomings of traditional overall learning by making full use of positive and negative samples to help the network learn a kind of 'mapping' to achieve the transformation from fog to fog-free and adding structural similarity loss to make the output image with more detailed edges. The colour distortion is mitigated. In addition, a data set RSI_Haze is proposed for remote sensing image defogging, and fogs with different transmittance are synthesized to obtain a data set closer to the real one with higher richness to train the defogging network, which makes the parameters of the network more robust and can remove fogs of different thicknesses adaptively. Experiments show that the network has a better recovery effect in high-resolution remote sensing images than other SOTA networks, enabling remote sensing images to play more value for human activities. [ABSTRACT FROM AUTHOR]

In this work, As60Cu40-xSex thin films were synthesized, and the pulsed laser deposition method was used to study the effected partial replacement of copper with selenium. The electrical characteristics and optical characteristics, as indicated by the absorbance and transmittance as a function of wavelength were calculated. Additionally, the energy gap was computed. The electrical conductivity of the DC in the various conduction zones was calculated by measuring the current and voltage as a function of temperature. Additionally, the mathematical equations are used to compute the energy constants, electron hopping distance, tail width, pre-exponential factor, and density of the energy states in variation zones (densities of the energetic extended states N(Eext), localize N(Eloc) and at the Fermi states N(Ef)). The acquired data also demonstrated that the selenium concentration obviously had an impact on the electrical conduction mechanics, energy states, and the level of randomization. [ABSTRACT FROM AUTHOR]

Cr:Al2O3 crystals with different Cr3 + concentrations were prepared by optical floating zone method, and cylindrical Cr:Al2O3 crystals with different diameters (2 mm to 13 mm) and lengths greater than 100 mm were prepared. The densities of powder rods, ceramic rods and crystals obtained at different stages of Cr:Al2O3 crystal preparation are measured to be 0. 928, 2.230 and 4. 051 g/cm3, respectively. XRD patterns show that Cr:Al2O3 crystal is α-Al2O3 phase. The transmission spectra show that the transmittance of Cr:Al2O3 crystal in visible light non-characteristic absorption band is more than 80%. The absorption spectra and photoluminescence excitation (PLE) spectra (monitoring 669 nm light) show that there are strong absorption bands at 418 and 559 nm, corresponding to the transitions of Cr3 + from 4 A2 to 4 T1 and from 4 A2 to 4 T2, respectively. Under the excitation of light with a wavelength of 559 nm, the photoluminescence (PL) spectra of Cr:Al2O3 crystals show a strong emission peak at 669 nm. At low Cr3 + concentration, the intensities of the peaks increase with Cr3 + concentration increasing, and reach the maximum value in Cr0. 006 0 Al1. 994 0 O3 crystal, and then decrease with the increase of Cr3 + concentration. [ABSTRACT FROM AUTHOR]

Aiming at the problems of cross-color or overcolor and dehazing residue in the traditional method of removing nonhomogeneous haze, a dehazing method for nonhomogeneous images based on adaptive scattering coefficient is proposed. Firstly, three kinds of haze density features are used to characterize the nonhomogeneous distribution of haze, and the positive correlation function between the atmospheric scattering coefficient and the haze concentration is innovatively established, which realizes the dynamic identification of the haze concentration of different pixels. Furthermore, the adaptive allocations of different atmospheric scattering coefficient values according to different haze concentrations at each pixel, and more accurate transmittance values are obtained. Secondly, the context regularization based on Robinson's high-order operator is used to constrain the transmittance, avoiding halo artifacts in the image after dehazing, and retaining image texture and detail information to the maximum extent. The experimental results show that the proposed method can pride better results in visual effects and objective indicators on both real haze images and nonhomogeneous haze images. [ABSTRACT FROM AUTHOR]

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Huygens' metasurfaces, as a class of artificial electromagnetic surfaces, have garnered significant interest due to their ability to effectively manipulate electromagnetic wave fronts. In this article, a Huygens' element with a simple design is discussed. The structure comprises a dielectric substrate sandwiched between a reverse-opening resonant ring and a pair of single-opening resonant rings. The proposed structure enables independent modulation of the electrical and magnetic response, particularly delivering transmittance amplitude of at least 0.8 and 0°–360° phase control simultaneously in a single double layer without vias. Based on this structure, we create a Huygens' metasurface focusing lens that gathers plane waves at the focal point. Then, a patch antenna is mounted onto this metalens to transform the radiated spherical waves into plane waves, increasing the antenna gain by up to 11 dBi. The experimental and simulated results demonstrate excellent agreement, demonstrating the usefulness of the proposed metalens and the importance of the designed Huygens-atom for metalens applications. [ABSTRACT FROM AUTHOR]

Quantum computing will play a crucial part in our security infrastructure for the coming years. Quantum networks can consist of direct optical fiber or free-space links. With the use of satellite channels, we can create a quantum network with higher coverage than using optical fibers where the distances are limited due to the properties of the fiber. One of the highest drivers of cost for satellite networks, apart from the cost of the technology needed for such systems, are the costs of launching and maintaining said satellites. By minimizing the satellites needed for a well-functioning quantum network, we can decrease said network’s cost, thus enabling a cheaper quantum internet. In this paper, we present an optical transmittance-based routing algorithm with which it is possible to conduct successful quantum entanglement transfer between terrestrial nodes. [ABSTRACT FROM AUTHOR]

Transmittance, haze and texture performance of new high twisted nematic(HTN)mode dichroic dye‐doped liquid crystal device under different voltages when power on and power off were studied. According to the elastic free energy theory of liquid crystal, two key phase transition voltages VPH and VHP of HTN mode liquid crystal were calculated. From a theoretical perspect, it was verified that the liquid crystal transition state under different voltages could correspond to the actual dimming performance, which could provide technical driving reference for other similar HTN device. Finally, based on the above analysis results, driving methods of three light dimming modes which included anti‐glare, privacy protect and high transparent mode were studied to meet the needs of different application scenarios. [ABSTRACT FROM AUTHOR]