Relative Refractive Index Research Articles

High capacity performance signature of micro optical mechanical system switches based fiber Bragg grating scheme implementation in optical WDM data routed center networks

Abstract This paper demonstrated the high capacity performance signature of micro optical mechanical system switches based fiber Bragg grating scheme in optical wavelength division multiplexing data routed center networks. The FBG reflectivity is simulated versus near infrared operating wavelength region with relative refractive index difference of Δn = 0.1 %. Required optical pump power, temperature increment and FBG power dissipation or consumption are demonstrated versus FBG wavelength spacing at pumping wavelength of 1,480 nm for doped/undoped fiber. Required FBG mechanical switching voltage, and required FBG mechanical/thermal switching time are clarified at pumping wavelength of 1,480 nm for doped/undoped fiber. Grating period and Bragg wavelength is studied against effective refractive silica/polymer FBG index.

Linear and Nonlinear Optical Properties of Symmetric and Asymmetric Double Triangular Quantum Dots Withinside the Presence of Magnetic Field

AbstractLinear and third‐order nonlinear optical absorption coefficients and relative refractive index changes in symmetric and asymmetric double triangular quantum dots are examined theoretically. The dependence of these optical properties on the magnetic field is examined. After calculating energies and wave functions within the effective mass and parabolic band approaches, analytical expressions of linear and nonlinear optical properties are obtained using the compact density matrix approach and iterative method. Numerical calculations are presented for typical GaAs/AlGaAs material. The results show that the magnetic field causes different effects on the and transitions. Moreover, the calculated results also reveal that the resonance frequency and nonlinear contribution are different in symmetric and asymmetric structures. As a result, it is concluded that the magnetic field plays a vital and important role in the electronic and optical properties of the system and can be used to tune the inter‐subband transitions and change the corresponding optical sensitivities.

A method of multi-bit optical coding by constructing Brewster angles to enhance photonic spin Hall effect

The photonic spin Hall effect, characterized by its polarization-driven spin-related displacement, has played an essential role in coding information processing. In this Letter, using a two-period double-layer dielectric plate, the displacement changes within the angle region are first observed, and a two-bit effective coding is achieved through non-uniform quantization of displacement values and coding. Afterward, by constructing Brewster angles (BAs), effective three-bit coding is achieved at the selected BA by dividing the angle domain. By changing the relative refractive index of the constituent materials (nB), effective coding is achieved at corresponding angles (45°–85°). By connecting two-bit and three-bit coding, a five-bit coding is fulfilled. By setting the last six invalid values, effective correspondence of 26 English letters is obtained. At the same time, the largest displacement peak itself is huge and varies accordingly with different values of nB. This work can provide some reference for designing optical coders.

Discovery of Quality by Design-Based Extraction Technology and the Quality Standard of Jinhua Finger Citron Essential Oil.

Jinhua finger citron is one of the traditional specialties of Jinhua with a long history of cultivation. The current study highlighted the advantages of using the quality by design approach to optimize the ultrasonic-assisted distillation extraction of Jinhua finger citron essential oil. The yield of Jinhua finger citron essential oil was regarded as a potential critical quality attribute. Potential critical process parameters were screened by the definitive screening design. Finally, the design space of the essential oil extraction process was constructed. The optimal operating space included an auxiliary NaCl concentration range of 9-12.00%, a soak temperature range of 30-50 °C, a distillation time range of 3.5-4.00 h, an ultrasonic power range of 200-300 W, a solid-liquid ratio range of 1:3-1:3.5, and a soak time range of 40-80 min. On this basis, the relative density, refractive index, and pH values of different batches of Jinhua finger citron essential oil were checked. The involved batches were analyzed by gas chromatography (GC), and gas chromatographic fingerprints were established by identifying major compounds, including d-limonene, γ-terpinene, and 5,7-dimethoxycoumarin. Based on the "quality by design" strategy, the extraction process of Jinhua finger citron essential oil established in this study was robust, reliable, and flexible.

Effects of hydrostatic pressure, temperature, and position-dependent mass on the nonlinear optical properties of triple delta-doped GaAs quantum well

In this study, we thoroughly investigate the impacts of hydrostatic pressure, temperature, and position-dependent mass (PDM) on the nonlinear optical properties of asymmetric triple δ-doped GaAs quantum wells. Our analysis covers total optical absorption coefficients, relative refractive index changes, nonlinear optical rectification, second harmonic generation, and third harmonic generation. Initially, we employ PDM to solve the time-independent Schrödinger equation using the diagonalization method under effective mass and parabolic band approaches, considering pressure and temperature dependencies. Utilizing the first four energy eigenvalues and eigenfunctions, we apply the compact density matrix method to compute the system’s nonlinear optical properties numerically. The results indicate a shift in optical property peak positions toward lower (higher) energy spectra with increasing hydrostatic pressure (temperature). Furthermore, the influence of PDM shifts the system’s optical properties toward the higher energy spectrum, resembling the effect of temperature. From an experimental and theoretical perspective, one of the topics that researchers work on most is GaAs-based δ-doped systems (δ-doped heterojunction bipolar transistors, δ-doped field effect transistors, δ-multiple independent gate field effect transistors, etc.). We believe these findings will provide valuable insights for the researchers involved in GaAs-based δ-doped optoelectronic device design.

Relative intensity noise management and thermal/shot noise control for high speed ultra high bandwidth fiber reach transmission performance

Abstract This work has clarified the relative intensity noise management and thermal/shot noise control for high speed ultra high bandwidth fiber reach transmission performance. Total link losses variations are clarified against ambient temperature and relative refractive index difference variations at 1,550 nm wavelength, 20 km fiber link length, and 45 % fluoride dopant ratio inside the fiber material cable. Besides the total link losses variations are demonstrated versus fiber link length and relative refractive index difference variations at 1,550 nm wavelength, room temperature, and 45 % fluoride dopant ratio inside the fiber material cable. Required optical signal per noise ratio (OSNR), electronic signal to noise ratio (SNR), and optimum gain variations are measured and analyzed versus the fiber link length and relative refractive index difference variations at 1,550 nm wavelength, room temperature, and 45 % fluoride dopant ratio inside the fiber material cable.

The Nonlinear Optical Properties of Self-Assembled InAs/GaAs Quantum Dot: Effect of Hydrostatic Pressure and Temperature

In this study, we have investigated the effects of temperature (T) and hydrostatic pressure (P) on both the nonlinear and linear optical properties of an InAs/GaAs core/shell quantum dot (QD) system with a Screened-Modified Kratzer potential (SMKP). To achieve this objective, we calculated the energy levels and their corresponding wave functions of the structure using the diagonalization method within the framework of the effective mass approximation. Analytical expressions for the absorption coefficients (ACs) and relative refractive index changes (RRICs) were derived using the compact-density-matrix approach. In our numerical calculations, we first determined the variation of the SMKP dependence, the dipole transition matrix element, and the electron energies of the ground (1s) and first excited state (1p) over a range of hydrostatic pressure (P) and temperature (T). As a result, the obtained numerical calculations revealed that changes in P and T influence both the magnitude and position of the resonant peaks that define the ACs and RRICs

Nonlinear optical properties of GaAs/AlGaAs asymmetric triple quantum wells designed for quantum cascade lasers: Effect of externally applied electric and magnetic fields

We explore the impact of external fields on the absorption coefficients and relative refractive index changes in a quantum cascade laser profile-like heterostructure that consists of a triple asymmetric quantum well. Firstly, we solve numerically the time-independent Schrödinger equation by using the diagonalization method under the effective mass and parabolic band approaches, to obtain the energy levels and wavefunctions. Then, we evaluate the optical coefficients from the analytical expressions derived from the compact density matrix method. The obtained results put forth that the resonant peaks of optical coefficients shift to higher (lower) energies by increasing the value of the electric (magnetic) field. These results indicate that it would be possible to adjust the optical properties of these structures to the desired range with external fields. As a result, we hope that new optoelectronic devices based on asymmetric triple quantum wells can be developed using the features found here.

Interaction of an electron and a uniformly charged spherical donor impurity

In this study, we propose an interaction potential between an electron and a uniformly charged spherical donor impurity in a quantum dot and numerically solve the Schrödinger equation using the finite difference method. We investigate the effects of the potential depth, donor radius, temperature, and hydrostatic pressure on the electronic and optical properties of an electron-donor impurity in a quantum dot, including absorption coefficients and the total change in the relative refractive index during the transition of an electron from the ground (1s) to excited (2p) states in the conduction band. Our findings indicate that an increase in donor radius or temperature leads to a red shift in the optical response, holding the parameters constant. Conversely, an increase in potential depth or hydrostatic pressure induces a blue shift in the optical response under the constant parameters.

Revisiting the scattering regime map based on transport scattering coefficient for dielectric particulate medium

The independent scattering assumption is frequently employed in radiative transfer, as it is applicable to numerous scientific and practical scenarios involving sparsely distributed scatterers. However, dependent scattering effects must be considered if the particle distribution is not sparse, which requires a relatively more rigorous analysis. A scattering regime map that summarizes the conditions where the independent scattering assumption can be used safely was established in the 1980s. The validity of this regime map and corresponding transition criteria has been questioned due to revealed inaccuracies in certain portions of the map based on the recent experimental studies. This study aims to reevaluate the regime map for dielectric particulate medium through numerical simulations utilizing dense medium radiative transfer theory relying on static structure factor for incorporating the effects of dependent scattering. The transport scattering coefficient, encompassing both the scattering coefficient and the asymmetry parameter, is employed as the metric of evaluation as it accounts for both the quantitative and directional behavior of the scattering. Besides, it also reflects the behavior of reflectance/transmittance closely, which is presented by comparing the regime maps based on transport scattering coefficient and reflectance. While the resulting modified regime map agrees mostly with the established map, it corrects the parts where discrepancies were observed so that the modified map is in agreement with all available data. Moreover, the effects of particle size distribution and material properties are also investigated and it was found that a regime map for lower relative refractive index miss-match between particle and medium produces a demarcation line that is more conservative.

Infrared relative dielectric permittivity and refractive index on the spherical CdSe/ZnS heteronanocrystals with self-consistent field

We deal with allowed-subband quantum states of two-electron in a semiconductor spherical core/shell quantum dot. Within framework of the infrared transitions, solving the Schrödinger-Poisson equation for repulsive interactions on the conduction-subbands, we obtain energy shifts in the absorption peaks of dielectric functions . The energy eigenvalues of the CdSe/ZnS nanocrystal have been computed as a function of the layer thicknesses through self-consistent field. The optical absorption transitions related to D − and D 0 donor states, have been plotted considering linear dielectric permittivity. The obtained values of dielectric constant for CdSe monolayers are compared with 3D simulation results. Refractive index and absorption coefficient under 3.0 nm CdSe core radius have been also presented as a function of infrared photon energies.

Hydrostatic pressure and temperature effects on nonlinear optical properties in harmonic-Gaussian asymmetric double quantum wells

The paper examines the linear and non-linear optical characteristics of an electron in harmonic Gaussian asymmetrical double quantum wells, taking into account thermodynamic variables such as temperature and hydrostatic pressure. Numerical calculations by considering the effective mass and parabolic band approximation are performed. The electron contained within an asymmetric double well generated by the sum of a parabolic and Gaussian potential has its eigenvalues and eigenfunctions determined using the diagonalization approach. For nonlinear optical coefficients, the density matrix expansion is used. Wavefunctions and energy levels vary as an effect of the applied fields. In harmonic Gaussian asymmetrical double quantum wells, the total optical absorption coefficient (TOAC), the relative refractive index changes (RRIC), and second harmonic generation (SHG) have all been theoretically investigated. The magnitude and position of the resonant peaks are significantly influenced by the hydrostatic pressure and temperature effects. With controllable coupling and externally applied hydrostatic pressure and temperature, the potential model presented in this study can be used to simulate and manipulate the optical and electronic properties of the asymmetric double-quantum heterostructures, such as double quantum dots and wells.

Physicochemical Characteristics, Fatty Acid Profile, and In Vitro Antioxidant Activity Evaluation of Sacha Inchi Seed Oil from Indonesia

Free radicals can cause damage to the structure of the dermis layer, which makes skin lose its elasticity and leads to the formation of wrinkles. A strategy to prevent this problem is by using antioxidants. A plant that has been reported to contain good antioxidant activity is sacha inchi seed (Plukenetia volubilis L.); apart from that, its oil has quite a high omega-3 content and potentially can act as an anti-aging agent stimulating the skin-cell-regeneration process, maintaining skin moisture and elasticity and stimulating collagen production. This research aims to analyze the physicochemical characteristics and determine the fatty acid profile, the levels of vitamins A, D, and E, and the antioxidant activity of sacha inchi seed oil. This research was conducted through eight main stages: sacha inchi seed extraction, quality parameters checking, phytochemical screening, determining fatty acid profiles, vitamin analysis, antioxidant activity tests, microbiological contamination tests, and heavy-metal contamination tests. In this study, quality inspection results were obtained: organoleptic form (liquid), color (yellow), odor (typical), relative density value (0.91 g/cm3), acid number (0.38 ± 0.02 mg/g), peroxide value (11.01 mEq/Kg), iodine value (179.32 g/100 g), and refractive index (1.479). The phytochemical screening results of sacha inchi seed oil were positive for containing flavonoids, triterpenoids, and steroids. The results of the fatty acid profile were omega-3 (48.5%), omega-6 (34.8%), and omega-9 (7.7%). The results of the vitamin contents analysis were vitamin A (123.42 mg/100 g), vitamin D (899.46 mg/100 g), and vitamin E (145.06 mg/100 g). The antioxidant activity test showed an IC50 value of 8.859 ppm (very strong), and the microbial and heavy-metal contamination tests were negative.

Modeling the performance of perovskite solar cells with inserting porous insulating alumina nanoplates

Peng et al. [Science 379 683 (2023)] reported an effective method to improve the performance of perovskite solar cells by using thicker porous insulator contact (PIC)-alumina nanoplates. This method overcomes the trade-off between the open-circuit voltage and the fill factor through two mechanisms: reduced surface recombination velocity and increased bulk recombination lifetime due to better perovskite crystallinity. From arguments of drift-diffusion simulations, we find that an increase in mobility and carrier recombination lifetime in bulk are the key factors for minimizing the resistance-effect from thicker PICs and achieving a maximum power conversion efficiency (PCE) at approximately 25% reduced contact area. Furthermore, the partially replacement of perovskite films with thicker PICs would result in a reduction in short-current density, but the relative low refractive index of the PICs imbedded into the high refractive index perovskite creates light trapping structures that compensate for this loss.

Slowdown of group velocity of light in dual 1480 nm hybrid pump cascade structure of Er3+-doped optical fiber at room temperature

In this paper, a general theory of slow light transmission in dual 1480nm hybrid pump cascade structure of Er3+-doped optical fiber at room temperature is presented. Our objective is to compare the dual 1480nm hybrid pump cascade structure with the 1480nm and 980nm hybrid pump cascade structure in relative modulation attenuation, time delay, fractional delay, group velocity, refractive index, and signal optical loss. Through theoretical calculation, the maximum time delay is increased by 1.111 times and 1.162 times, and the maximum fractional delay is increased by 1.091 times and 1.132 times when the pump power ratio M=0.5 and 0.75. The loss coefficient is reduced to 0.1 when M=1. The results show that compared with the previous research methods, the dual 1480nm hybrid pump cascade structure can obtain larger time delay, fractional delay and smaller loss, which may have important applications for the optimization of optical communication systems.

Linear and nonlinear electric and magneto-optical absorption coefficients and relative refractive index changes in WxMo1−xS2 monolayer: Role of tungsten contents

In this work, we study the electric and magneto-optical absorption coefficients (ACs) and relative refractive index changes (RRICs) in W[Formula: see text]Mo[Formula: see text]S2 ternary alloys under the control of tungsten contents using the compact density matrix approach. With the influence of external electric and magnetic fields, the results show that there are a series of resonant peaks for both intra-band and inter-band transitions. With an increase in W-concentration and electric and magnetic fields, the resonant peaks give a blue (red) shift and reduce (increase) their amplitudes. These results suggest a potential application of monolayer W[Formula: see text]Mo[Formula: see text]S2 in future nanoscale electronic and magneto-optical devices.

Visualization of Radiation Scattering Indicatrix on a Polydisperse System of Spherical Particles

The article is devoted to solving the direct problem of light scattering on an ensemble of spherical polydisperse particles. The paper presents an algorithm for computer simulation of the optical radiation scattering indicatrix by a particle system based on the theory of G. Mie. The influence of the relative complex refractive index of scattering centers and their size distribution, wavelength and polarization state of incident light on computer models of scattering indicatrix is investigated. The practical significance of the results obtained lies in the fact that computer models of scattering indicatrix are useful in the experimental study of dispersed systems by static light scattering for the optimal choice of installation parameters and experimental conditions and, more importantly, in solving the inverse problem of the static light scattering method to restore the characteristics of nanoparticles from experimental data.

Stable, self-biased Cs2AgBiBr6 thin-film based photodetector by three-step vapor-deposition

A lead-free, pure phase double perovskite Cs2AgBiBr6 thin film (TF) is fabricated on an ITO glass plate through a three-step sequential vacuum thermal evaporation method followed by annealing. X-ray diffraction (XRD) analysis of the synthesized material revealed a cubic phase with a lattice constant of α = 11.26 Å. The TF exhibits UV and visible absorption with a bandgap estimated at 2.31 eV (303 K) and a red shift of 0.04 eV (363 K). The optical absorption spectrum is simulated using the modified band anti-crossing (BAC) model, determining the Cs2AgBiBr6 TF's theoretical relative refractive index (r.i.) as 2.10 (303 K) and 1.90 (363 K). Furthermore, a photodetector based on Ag/Cs2AgBiBr6/ITO/glass architecture was fabricated, showcasing excellent stability and self-powered photodetection properties under continuous illumination across a wide temperature range of 303–373 K. The device demonstrates a fast temporal response (13/9 ms), a responsivity of ∼1.0 × 10−4 A/W, and a detectivity of ∼2.5 × 107 Jones. Light sensitivity measurements reveal that the device is twice as sensitive at 373 K compared to room temperature, with negligible (1%) degradation in light sensitivity after 60 days of storage under normal ambient conditions.

Terahertz Properties of Common Microwave Dielectric Materials

Traditional microwave design and fabrication techniques have been adopted into the terahertz domain. Understanding the properties of microwave dielectric materials at terahertz frequencies is critical for accurate component design. Nevertheless, terahertz properties for common microwave dielectric materials are largely unknown. Hence, this paper presents the relative permittivity, loss tangent, refractive index, and extinction coefficient for such materials, including microwave substrates and low-temperature co-fired ceramics (LTCCs), within the 0.1 to 3.5 THz range. Terahertz time-domain spectroscopy (THz-TDS) and a vector network analyzer produce accurate material parameter results. The material parameters presented in this paper serve as a valuable resource for component design at terahertz frequencies.

Nonlinear optical properties of modified Möbius squared potential well: influence of electric and magnetic fields

ABSTRACT This work presents a numerical study on the electronic and optical properties of modified Möbius squared potential well in the presence of static electric and magnetic fields. The potential well is formed within GaAs/AlGaAs hetero structures. Schrödinger’s equation is solved within the framework of effective mass and envelope wave function approximations to get the wave functions and their corresponding energies of states. The optical absorption coefficients and relative refractive index changes are calculated via the expressions derived from the compact density matrix approach. The numerical results present strong blue shifts on the optical responses of modified Möbius squared potential well when the external electromagnetic fields are strengthening.