Variation Of Optical Parameters Research Articles

Quantitative evaluation of the impact of variation of optical parameters on the estimation of blood hematocrit and oxygen saturation for dual-wavelength photoacoustics

Photoacoustic (PA) spectroscopy is considered to be one of the most effective ways to measure the levels of hematocrit (H) and oxygenation saturation (SO2) of blood, which are essential for diagnosing blood-related illnesses. This simulation study aims to investigate the impact of individual optical parameters, i.e., optical absorption coefficient (μ a ), scattering coefficient (μ s ), and anisotropy factor (g), on the accuracy of this technique in estimating the blood properties. We first performed the Monte Carlo simulations, using realistic optical parameters, to obtain the fluence maps for various samples. The wavelengths of the incident light were chosen to be 532, 700, 1000, and 1064 nm. Thereafter, the k-Wave simulations were executed, incorporating those fluence maps to generate the PA signals. The blood properties were obtained using the PA signals. We introduced variations in μ a , μ s , and g ranging from −10% to +10%, −10% to +10%, and −5% to +1%, respectively, at 700 and 1000 nm wavelengths. One parameter, at both wavelengths, was changed at a time, keeping others fixed. Subsequently, we examined how accurately the blood parameters could be determined at physiological hematocrit levels. A 10% variation in μ a induces a 10% change in H estimation but no change in SO2 determination. Almost no change has been seen for μ s variation. However, a 5% (−5% to 0%) variation in the g factor resulted in approximately 160% and 115% changes in the PA signal amplitudes at 700 and 1000 nm, respectively, leading to ≈125% error in hematocrit estimation and ≈14% deviation in SO2 assessment when nominal SO2=70%. It is clear from this study that the scattering anisotropy factor is a very sensitive parameter and a small change in its value can result in large errors in the PA estimation of blood properties. In the future, in vitro experiments with pathological blood (inducing variation in the g parameter) will be performed, and accordingly, the accuracy of the PA technique in quantifying blood H and SO2 will be evaluated.

A comparative study of DFT and experimental investigations for exploring the effect of Ti doping on the electronic, structural, and optical properties of Cu2O

The current study presents the influence of Ti doping on the electronic, structural, and optical properties of Cu2O. The investigation employs a comparative approach, integrating theoretical calculations using density functional theory and experimental outcomes. Density of states spectra depicted the maximum contribution of Cu-d and O-p in the valence band, whereas Ti-d states filled the conduction band. Structural changes induced by Ti doping, including variations in peak intensity, crystallite size, and defects were examined in detail by X-ray diffraction analysis. The field emission scanning electron microscopy described grain morphology significantly changing upon Ti doping. Optical properties were scrutinized to determine variations in optical parameters. For both un-doped and Ti-doped Cu2O, the experimentally measured band gap was found to be decreased, ranging from 2.05 eV to 1.69 eV. The comparative studies enable a valuable understanding of the effectiveness of Ti doping in modifying the properties of Cu2O.

First principle and experimental investigations on Mg-doped ZrO2 thin films for electronic, thermoelectric, and optical application

To study the Mg-doped ZrO2, the electronic, thermoelectric, and optical properties were characterized by first principle as well as experimental techniques. For experimental observations, the samples for pure ZrO2 and Mg-doped ZrO2 thin films were prepared. A noticeable difference was observed between the results of electronic, thermoelectric, and optical properties of pure and Mg-doped ZrO2 thin films. The electronic properties extracted from simulations show that Mg-doped ZrO2, Mg-s, Zr-d, and O-p states provide the main contributions. The electrical conductivity and Seebeck coefficient present an increasing trend with doping of Mg content. The absorption coefficient trend shows that the material becomes more absorbing with the increase in Mg content. The refractive index reduces from ∼2.2 to ∼1.8. The content of Mg carries corroborates the substantial variation in optical parameters with varying energy ranges. The comparison is carried out between the results of optical properties deduced through simulations and spectroscopic ellipsometry.

OCT评估超声介导下表皮真皮层的光学参数变化规律的研究

OCT评估超声介导下表皮真皮层的光学参数变化规律的研究

Isotropic pressure induced structural, electronic, photocatalytic, elastic and mechanical properties of RbPbF3: GGA-PBE and HSE03 based computational estimation

The main objective of this study is to present a comprehensive computational analysis, with Generalized Gradient Approximations (GGA) and Heyd–Scuseria–Ernzerhof (HSE03) correlation functionals, of the structural, optoelectronic, photocatalytic and elastic properties of Rubidium Lead Fluoride (RbPbF3) under the systematic isotropic pressure range of 0–55 GPa. Under stress a systematic decrease in lattice parameters and band gap (4.869 eV − 1.105 eV) is observed upto 55 GPa. For comprehensive evaluation of band gap, PDOS and EPDOS have also been determined. Photocatalytic properties of RbPbF3 under stress demonstrate the best photocatalytic water-splitting potential, aligning with the band gap estimation. The significant variation in optical parameters is found with a varying stress array from 0–55 GPa. Optically this compound can be utilized as a UV detector because absorption bands are seen in the UV spectrum. The material exhibits mechanical stability, and ductile behavior, with ionic and covalent bonding. The anisotropic nature is observed in our estimated results.

Variation of optical parameters of physically stacked polyvinylidene chloride films with thickness and wavelength

Variation of optical parameters of physically stacked polyvinylidene chloride films with thickness and wavelength

Long-range surface plasmon resonance biosensors with cytop/Al/Perovskite and cytop/Al/MoS2 configurations

In this paper, long range surface plasmon resonance (LRSPR) biosensors with cytop/Al/Perovskite and cytop/Al/MoS2 configurations have been theoretically investigated and compared with standard LRSPR biosensor with cytop/Al/graphene configuration. To calculate the optical properties of considered configurations for the desired application, transfer matrix method for TM mode has been used to obtain reflectance. The sensitivity of the considered configurations for designed biosensors has been investigated with variation of optical parameters of the structure. A new configuration of LRSPR biosensors based on Al- MoS2 or Al-Perovskite has been proposed to enhance sensitivity, detection accuracy, and efficiency. The maximum value of sensitivity of the proposed Al-Perovskite based LRSPR biosensor is found to be 4847 RIU−1. Moreover, the sensitivity of Al-MoS2 and Al-Peroskite based LRSPR biosensors show nearly 10% and nearly 30% more optical responses respectively than the Al-graphene based LRSPR biosensor.

Correlation of annealing temperature on physico-chemical properties and electrochromic performance of nebulizer spray-coated NiO films

Nickel Oxide (NiO) thin films were deposited over glass and FTO substrates using nebulizer spray pyrolysis technique. The influence of various annealing temperatures (400, 450, 500 and 550 °C) on film stoichiometry and its subsequent effect on physical and electrochromic properties were studied. Structural information, chemical state and change in morphological properties of the deposited films concerning the film stoichiometry and concentration of cationic vacancy (VNi) induced Ni3+ ions are discussed with the help of XRD, XPS, HR-SEM, EDS and AFM. The variation of optical parameters associated with the presence of defects in NiO is reported from UV-Vis spectroscopic analysis. Electrochromic performance of the prepared films was evaluated using cyclic-voltammetry, chronoamperometry, chronocoulometry and iono-optical electrochemical measurements. Enhanced electrochromic behavior with a rapid switching response time of 0.3/0.5 s of bleached/colored states respectively was realized for NiO film with relatively higher concentration of Ni3+.

Simulation Study on the Optimization of Photon Energy Delivered to the Prefrontal Cortex in Low-Level-Light Therapy Using Red to Near-Infrared Light

Brain functions have been proved to be affected by external stimuli. Low-Level-Light Therapy (LLLT) using near-infrared photons is one of the effective ways to modulate the hemodynamic activities in the brain. However, the biphasic hormetic dose-response where bioenergetics are stimulated at a low dose and inhibited at a high dose is well observed in all photon stimulations. The amount of photon energy delivered to the brain are affected by the wavelength as well as the multilayered head structure with variations of optical parameters (OPs). A real 3D volume head model is built for each participant in this study, and the boundary conditions of each OP in each layer is considered. The Monte Carlo simulation with wavelengths ranging from 650 nm to 1064 nm is implemented to investigate the energy delivered to the brain under different radiation profiles. Results show that 1064-nm photons penetrate deeper than 810-nm photons except for scalp absorption at the lower bound due to low melanin content. Collimated-beam radiation is better than diverging-beam due to a more uniform intensity distribution at the scalp surface. Further research to optimize LLLT dosage for each individual is imperative due to the high inter-person variability in structure and OPs.

The Replacement of Seashells with Calcite in White Ceramic Glaze Preparation

In this study, the effect of seashell utilization as a replacement for calcite on the surface features and optical properties of white ceramic glazes was investigated. As received seashells collected from Black Sea beaches of Samsun, Turkey and purified seashells at 700°C for 1 h were used as calcite replacement by 15 wt.%. Seashell powders were incorporated to white glaze compositions which are applied on the surface of different fired clay bodies such as red clay, chamotte, white and porcelain by dipping technique. Next, the glazed green bodies were sintered at 1100ºC for 8 h. Following to TG-DTA, heating microscope, XRD and optical analysis, the obtained results exhibited that as received seashell powder (SP-1) was composed of calcite (CaCO3), whereas purified seashell powder (SP-2) comprised aragonite (CaCO3) and calcium oxide (CaO). The iron (hematite) content in red clay and the impurities in seashells composition caused specks and crawlings on the surface of glazed red clay bodies and of some glazes containing seashell, respectively. In generally, the higher CaO content in SP-2 enhanced gloss (60°) values, and whiteness values of most glazed surfaces were closed to each other. The color of chamotte bodies increased redness-greenness values. The variations in optical parameters were mainly associated with the difference in body compositions. SP-1 contained glaze, applied on porcelain body, was selected as optimal because that had 33 gloss value, high whiteness (87) and no surface defect. Therefore, the utilization of as received seashells by 15 wt.% as calcite replacement allows eco-friendly and cost-effective production of white ceramic glazes without any additional heat treatment.

Pressure dependent elastic, electronic, superconducting, and optical properties of ternary barium phosphides (BaM2P2; M = Ni, Rh): DFT based insights

Density functional theory based investigations of structural, elastic, electronic band structure, and optical properties of superconducting ternary phosphides (BaM2P2; M = Ni, Rh) have been carried out. Calculated ambient condition properties are compared with experimental and theoretical results, where available. Pressure dependent electronic density of states at the Fermi level, N(EF), and the Debye temperature, θD, have been explored and their effect on the superconducting transition temperature have been disclosed. N(EF) shows nonmonotonic pressure dependence in BaNi2P2. Pressure dependence of N(EF) for BaRh2P2, on the other hand, is systematic. Pressure dependence of N(EF) affects superconducting transition temperature significantly. Debye temperature increases with increasing pressure. Variation of optical parameters with photon energy show metallic behavior complementing the features of electronic band structure calculations. Absorption coefficient of BaNi2P2 exhibits strong optical absorption in ultraviolet region, while BaRh2P2 absorbs photons over a wider energy band including the entire visible range. Reflectivity spectra for both BaNi2P2 and BaRh2P2 reveal that they are strong reflectors of visible light and BaNi2P2 in particular holds significant promise to be used as coating material to reduce solar heating.

Real time executable model for dynamic heat flow analysis of a solar hydrogen reactor

Abstract A real time executable model developed for dynamic heat analysis of a solar hydrogen reactor is described and characterized. To calculate the local distribution of radiation caused by multiple reflection inside the solar receiver the radiosity method is used. Significant optical characteristics including reflectance, transmittance and absorption are investigated related to the used materials and operating conditions. Furthermore, the influence on the model behavior is presented by variation of optical parameters. Simulation results are presented, which show good agreement with experimental data.

Effect of annealing temperature on structural and optical properties of gallium oxide thin films deposited by RF-sputtering

We have investigated structural and optical properties of gallium oxide (Ga2O3) thin films deposited on pre-cleaned fused quartz substrates at room temperature by RF sputtering method. The as-prepared and annealed Ga2O3 thin films are characterized by X-ray diffraction, energy dispersive X-ray fluorescence, fluorescence spectrometer and a double beam spectrophotometer. The variations in optical parameters of Ga2O3 thin films before and after annealing are reported. The optical parameters such as optical band gap, photoluminescence emission peaks, refractive index, single oscillator energy, plasma frequency and dispersion energy are determined before and after annealing. The probable image on the microstructure and optical features of Ga2O3 thin films before and after annealing is constructed.

WITHDRAWN: Phonon polariton dispersion of dielectric superlattice at various pressures in low dimensional systems

The variation of optical parameters under an external hydrostatic pressure is studied for the bulk material such as GaAs & AlAs. Hence the behavior of phonon polaritons modes in Low dimensional [LD] system is studied with pressure. It is found that the polaritonic gap in the system is found to be constant irrespective of the pressure values, but it is shifted to higher frequency region with pressure.

Multiferroic BFO/BTO multilayer structures based magnetic field sensor

Optical properties of polar multifunctional oxides under the influence of magnetic field are of great importance for the materialization of magnetic field sensors and ultrafast optoelectronic devices. Surface plasmon resonance (SPR) technique is an eminently precise means suitable for interface inspection. In this report, an effort has been made to develop an optical magnetic field sensor based on BFO/BTO multilayered thin films prepared using pulsed laser deposition (PLD) technique. The sensing principle relies on SPR phenomenon where the variation in magnetic field has been sensed by examining the variation in optical parameters i.e. reflectance and refractive index. The deviation in refractive index of BFO/BTO multilayered thin films for varying magnetic field has been estimated in order to calibrate the sensor for efficient sensing.

Effects of substrate temperature and precursor amount on optical properties and microstructure of CVD deposited amorphous TiO2 thin films

In this research, TiO2 thin films were deposited on glass substrate by chemical vapor deposition using tetra isopropylorthotitanate as a precursor at low temperature. The TiO2thin films were formed without using an oxygen source or annealing. Effects of substrate temperature and amount of the precursor on surface microstructure and optical properties of deposited TiO2 thin films were investigated. X-ray diffraction (XRD), UV-visible spectrophotometry and atomic force microscopy (AFM) were used to analyze the fabricated layers. The XRD analysis revealed that structure of all prepared layers was in amorphous phase. Analysis of AFM images showed that by increasing substrate temperature, the layer surfaces became rougher and simultaneously nanoparticle size was more uniform. Texture analysis revealed that increasing substrate temperature and decreasing precursor amount both increased surface isotropy. Thickness of layers was calculated by applying the Swanepoel method to the transmittance spectra. Variations in optical parameters were studied, including of optical band gap, refractive index, extinction coefficient, complex dielectric function, Urbach energy, single oscillator energy and dispersion energy. The results indicated that optical properties were functions of substrate temperature and precursor amount.

Ferroelastic phase transition in Cu6PS5Br1-xClx mixed crystals

ABSTRACTCu6PS5Br1-xClx mixed crystals were grown by chemical vapour transport. Optical absorption edge and optical polarization measurements were performed in the temperature range 77–320 K. The influence of anionic Br→Cl substitution on the phase transitions in Cu6PS5Br1-xClx mixed crystals is studied. Compositional dependence of the ferroelastic phase transition temperature for Cu6PS5Br1-xClx mixed crystals is obtained. The variation of optical parameters at ferroelastic phase transition is analyzed.

Effect of potassium chromate nanoparticles on the optical properties of poly (methyl methacrylate) (PMMA) films

In this work, the authors have presented a study on the variation in optical parameters that occur on doping Poly-methyl-metha crylate (PMMA) thin films with Potassium chromate (K2CrO4) by different weight percentages (1%,2%, 5% and 10%). These pure PMMA and its composite films are of thickness ∼100m and have been synthesized using the solution cast technique. The absorbance (A) and transmittance (T %) spectra of these films were recorded in the wavelength range (300-1100) nm using EI 2375 UV-VIS double beam spectrophotometer. From the obtained data, the optical parameters viz. absorption coefficient, extinction coefficient), finesse coefficient (F), refractive index (, real and imaginary parts of dielectric constant , optical conductivity and optical energy gap for indirect transition were evaluated and are found to show variation with increase of K2CrO4 concentration in the mentioned wavelength range.

Electron beam induced modifications in the microstructure of PVA/Li2B4O7 polymer films: Positron annihilation study

The films of 5 wt% Lithium Tetra Borate (Li2B4O7) doped Poly(vinyl alcohol) (PVA) were prepared by solution casting method. The prepared films were irradiated with different doses of 8 MeV electron beam. Fourier Transform Infrared (FTIR) Spectroscopy, UV–Visible Spectroscopy, electrical conductivity measurements and Positron Annihilation Lifetime (PAL) Spectroscopy were used to study the effects of electron radiation on the microstructure and properties of these films. The FTIR results show that the radiation induced chain scission in Li2B4O7 doped PVA, which affects the physical properties of the composite film. The variation of optical parameters for instance optical energy band gap, activation energy were obtained from UV–Visible absorption spectra, which reveals the formation of additional energy levels within the band gap due to the creation of defects and carbonaceous clusters upon irradiation. The conductivity of the sample was found to increase as the electron dose increased. It was found from the PAL study that the free volume size of the polymer increases with electron dose, which facilitates the micro-Brownian motions of the segmental polymer chain backbone. Consequently the motion of Li+ ions within the polymer segment will be speeded up. Accordingly ion transport within the polymer matrix strongly depends on rearrangement of free volume adequate to allow ion transport.

Optical properties of alkaline earth borate glasses

Borate glasses containing fixed concentrations of heavy metal oxides (MO= ZnO, PbO, TeO2, Bi2O3) and alkaline earth oxides (R= Mg, Ca, Sr, Ba) are prepared by melt quenching technique. The optical band gap values are estimated from the optical absorption spectra using absorption spectrum fitting (ASF) method. The values of electronic polarizability, optical basicity and interaction parameters of the glass were discussed. The increment of refractive index values in each series is attributed to the substitution of alkaline earth oxides of increasing mass. Optical band gap (Eopt) values decreased with the replacement of RO oxides in the glass matrix. The cut-off wavelengths have shown a red shift with composition. The decrease in optical band gap values and consequently increase in Urbach’s energies confirms more extension of the localized states within the band gap. As a result there shall be an increase in the disorder of the glass network. The variation in optical parameters is owing to substitution of RO oxides in MO-B2O3 glass network.Keywords: alkaline earth borate glasses, optical band gap, Urbach energy, refractive index, electronic polarizability, molar refraction