Characteristics Of Optical Radiation Research Articles

First-principles calculations to investigate structural, elastic, electronic, and optical properties of XSrCl3 (X = Li, Na)

The computational analysis of the compounds XSrCl3X=Li and Na is the subject of this research work. We utilized Density Functional Theory (DFT) to analyze the structural, optical, elastic, and electronic characteristics of XSrCl3(X=Li and Na) using the WIEN2K software. Birch Murnaghan curve optimization is performed to ascertain the structural details of both compounds. Using structural analysis, we learned that every compound displays a stable structural state at its optimum or ground state. The IRelast Package, which calculates elastic constants, is used to determine the elastic characteristics. Calculating these elastic characteristics reveals the compound's ductile or brittle nature, isotropy or anisotropy, and mechanical stability. Both materials are anisotropic and stable, as shown by an evaluation of elastic constants. Examining the Cauchy pressure, Poisson's ratio and Pugh ratio reveals that LiSrCl3 is a ductile compound while NaSrCl3 is brittle. We used generalized gradient approximation (GGA) to examine the electrical characteristics (Band Structure and Density of States). According to their computed band structures, these substances have wide indirect energy band gaps (R-Γ), or 3.57 eV for LiSrCl3 and 3.62 eV for NaSrCl3, which are indicative of semiconducting properties. To quantify the involvement of electronic states in the band structure, total and partial densities of states (TDOS and PDOS) are utilized. The optical characteristics of radiation up to 15 eV are estimated. Following an investigation of their optical properties, we measured these compounds' refractive indexes, absorption coefficients, and reflectivity. According to the anticipated electronic structure, the major optical spectrum peaks are listed.

Multi-spectral Characteristics of Arc Discharge in Switch Cabinet

The partial discharge (PD) in high voltage switch cabinet might develop into non-penetrating or penetrating arc under extreme conditions, which can lead to insulation failure in severe case. From the optical radiation characteristics of discharge, an optical detection method for abnormal arc was proposed. Multi-spectral characteristics of arc discharge were obtained by the synchronous monitoring of ultraviolet, visible, and infrared optical signals, and the average intensity of light pulse, average light intensity ratio and the light intensity ratio of three bands were analyzed. The results show that the average light pulse intensity of arc discharge and the proportion of three-band light intensity have obvious characteristics and there is a good corresponding relation between the amplitude of discharge light signal and the applied voltage.

Reconfigurable Radiation Angle Continuous Deflection of All-Dielectric Phase-Change V-Shaped Antenna.

All-dielectric optical antenna with multiple Mie modes and lower inherent ohmic loss can achieve high efficiency of light manipulation. However, the silicon-based optical antenna is not reconfigurable for specific scenarios. The refractive index of optical phase-change materials can be reconfigured under stimulus, and this singular behavior makes it a good candidate for making reconfigurable passive optical devices. Here, the optical radiation characteristics of the V-shaped phase-change antenna are investigated theoretically. The results show that with increasing crystallinity, the maximum radiation direction of the V-shaped phase-change antenna can be continuously deflected by 90°. The exact multipole decomposition analysis reveals that the modulus and interference phase difference of the main multipole moments change with the crystallinity, resulting in a continuous deflection of the maximum radiation direction. Thus, the power ratio in the two vertical radiation directions can be monotonically reversed from −12 to 7 dB between 20% and 80% crystallinity. The V-shaped phase-change antenna exhibits the potential to act as the basic structural unit to construct a reconfigurable passive spatial angular power splitter or wavelength multiplexer. The mechanism analysis of radiation directivity involving the modulus and interference phase difference of the multipole moments will provide a reference for the design and optimization of the phase-change antenna.

Digital Lighting Technologies to Control Galleria Mellonella Behavior

The authors found out that the greater wax moth (Galleria mellonella) harmed bee colonies by destroying up to 30 percent of honey in a beehive. They studied the results of experiments on controlling its behavior using a developed automated microprocessor system that maintained optical radiation sources duration.(Research purpose) To develop light technologies using a microprocessor-based automated system that allows controlling Galleria mellonella behavior by realizing attractive optical radiation characteristics.(Materials and methods) Galleria mellonella behavior was controlled by an automated system that the authors worked out for maintaining the required duration of the experiment and optical radiation parameters. The ATmega328 microcontroller was chosen as the main element of the developed microprocessor automated system. The authors created a program for it using visual programming FLProg version 5.3.0.(Results and discussion) The authors found that, regardless of the experiment duration, Galleria mellonella butterflies prefered radiation with 400 nanometers wavelength.(Conclusions) The authors determined that radiation with 400 nanometers wavelength and 10 minutes duration was attractive. They showed the ability to control Galleria mellonella behavior, luring butterflies to a specific place in the beehive with comfortable spectrum parameters. An automated system for controlling the greater wax moth butterfly behavior was developed on ATmega328 microcontroller by implementing attractive optical radiation characteristics.

COMPACT REFERENCE UVC LED SOURCE

There are a number of problems in metrological insurance in the UV spectral region. First, it is a significant reduction in the accuracy of the transfer of quantities from national standards of the corresponding optical quantities to working units in the CIE UV ranges. Second, when measuring in the UV CIE ranges, it is necessary to use a power meter with constant spectral sensitivity inside these ranges and zero outside it, which is very problematic due to the lack of high-quality UV filters. Third, the accuracy of the results of measuring optical characteristics of UV radiation is reduced significantly by difference in spectral distributions of the radiation intensity of the test and reference radiation sources. One of the promising ways to improve the accuracy of measurements in the UV spectral region is the use of reference radiation sources created based on LEDs, due to their stability and long lifetime.A compact reference UVC source based on state-of-the-art commercially available LED were designed and constructed at B.I. Stepanov Institute of Physics NAS of Belarus. The paper presents the design and results of the study of the optical characteristics of the radiation of the reference UVC LED source. A power density of the compact reference UVC LED source is >200 μW/cm2, which provides a fine level for calibrating UV radiometers in range UVC.

Digital Electrical Technologies to Control Insect Behavior

One of the main pests of bee colonies is the large wax moth, which can destroy up to 30 percent of the honey in the hive. Controlling the behavior of living objects can be based on their positive or negative response to optical radiation characteristics such as spectrum and exposure. Many insects see ultraviolet radiation. Authors suggest using an environmentally friendly method to attract butterflies with optical radiation. (Research purpose) The research purpose is in developing digital electrical technologies using a microprocessor-based automated system that allows controlling the behavior of large wax moth butterflies (Galleria mellonella) by implementing attractive characteristics of optical radiation. (Materials and methods) Authors controlled the behavior of a large wax moth using a developed automated system for maintaining the required duration of the experiment and optical radiation parameters. The main element of the system is the ATmega328 microcontroller, the program for which was written using the visual programming of FLProg 5.3.0. (Results and discussion) The use of digital electrotechnologies using the developed microprocessor automated control system on the ATmega328 microcontroller and assembled on the Arduino Uno Board makes it possible to implement energy-saving environmentally friendly light electrotechnologies for controlling the behavior of large wax moth butterflies. Regardless of the duration of the experiment, Galleria mellonella butterflies prefer radiation with a wavelength of 400 nanometers. (Conclusions) The experiments confirm that the radiation with a wavelength of 400 nanometers lasting 10 minutes at a temperature of 32 degrees Celsius and a humidity of 60 percent was attractive. These comfortable spectrum parameters allow to control the behavior of Galleria Mellonella by luring butterflies to a specific location in the hive.

A two-frequency mode to control acoustic field distribution inside cylindrical lens

Acousto-optical (AO) interaction is one of the most effective principles for electronic control of the optical radiation characteristics. Further development of this approach may be related to the use of fluids as a working media. In this paper, it is proposed to optimize spatial distribution of the refractive index in acoustic lens by applying two frequencies simultaneously. The simulation results are given. The optimal frequency combinations in terms of the central lobe intenity are found.

Preliminary Observations from the China Fengyun-4A Lightning Mapping Imager and Its Optical Radiation Characteristics

The Fengyun-4A (FY-4A) Lightning Mapping Imager (LMI) is the first satellite-borne lightning imager developed in China, which can detect lightning over China and its neighboring regions based on a geostationary satellite platform. In this study, the spatial distribution and temporal variation characteristics of lightning activity over China and its neighboring regions were analyzed in detail based on 2018 LMI observations. The observation characteristics of the LMI were revealed through a comparison with the Tropical Rainfall Measuring Mission (TRMM)-Lightning Imaging Sensor (LIS) and World Wide Lightning Location Network (WWLLN) observations. Moreover, the optical radiation characteristics of lightning signals detected by the LMI were examined. Factors that may affect LMI detection were discussed by analyzing the differences in optical radiation characteristics between LMI and LIS flashes. The results are as follows. Spatially, the flash density distribution pattern detected by the LMI was similar to those detected by the LIS and WWLLN. High-flash density regions were mainly concentrated over Southeastern China and Northeastern India. Temporally, LMI flashes exhibited notable seasonal and diurnal variation characteristics. The LMI detected a concentrated lightning outbreak over Northeastern India in the premonsoon season and over Southeastern China in the monsoon season, which was consistent with LIS and WWLLN observations. LMI-observed diurnal peak flash rates occurred in the afternoon over most of the regions. There was a “stepwise” decrease in the LMI-observed optical radiance, footprint size, duration, and number of groups per flash, from the ocean to the coastal regions to the inland regions. LMI flashes exhibited higher optical radiance but lasted for shorter durations than LIS flashes. LMI observations are not only related to instrument performance but are also closely linked to onboard and ground data processing. In future, targeted improvements can be made to the data processing algorithm for the LMI to further enhance its detection capability.

Optical Radiation Characteristics of Laser-Induced Air Plasma and Jamming CCD Imaging Detector

We studied the characteristics of laser-induced air plasma optical radiation and jamming the imaging CCD detector. Optical emission spectra of the air plasma ranged from 400 to 700 nm are composed of individual spectral lines superposing on continuous radiation, while the continuum radiation is mainly due to bremsstrahlung and recombination radiation. The jamming threshold of the CCD imaging detector jammed by optical radiation of the laser-induced air plasma is 3.98 × 1010 W/cm2. With increasing laser intensity, the plasma expansion volume and spectral intensity will increase, the image quality of the CCD detector will deteriorate, and the jamming area on the CCD detector will become larger. The experimental results indicate that the jamming effect of laser-induced plasma radiation on CCD detectors can overcome the shortcomings of a single-wavelength laser use, which is important for improving the optoelectronic jamming effect.

OPTICAL AND COLORIMETRICAL CHARACTERISTICS OF STRAINED LiF CRYSTALS UNDER X-RAY IRRADIATION

Here there were investigated the х-irradiation influence on the optical characteristics of LiF crystals and the colorimetric characteristics of optical radiation passing through crystals with different doses of irradiation. It was established that change of irradiation dose in the interval 0…1057 Р leads to reduce of absolute value of coordinates of the color and brightness of the radiation, passing through the crystal, but the color of the radiation thus remains constant.

Mathematical model of an acousto-optic switch for fiber-optic communication lines

In this study, the characteristics of optical radiation transmitted through the elements of a fiber-optic acousto-optic (AO) switch were investigated. The transmission efficiency of the optical signal and the insertion losses were determined. We proposed a mathematical model of an AO switch for fiber-optic communication lines; the model describes the propagation of an optical signal as the transmission of Gaussian radiation between the input and output fibers. The designed mathematical model enables the determination of the amplitudes, intensities, and power ratios of the signals in the input and output optical fibers, as well as the propagation pattern of the optical radiation and the radiation attenuation by the optical elements. Moreover, it allows the estimation of the optical signal transmission efficiency and the insertion losses.

Characteristics of lightning signals over the Tibetan Plateau and the capability of FY-4A LMI lightning detection in the Plateau

ABSTRACTBecause of its topographic features, lightning flashes are unique over the Tibetan Plateau. The Lightning Mapper Imager (LMI) on board the launched China’s Fengyun (FY)-4A geostationary satellite is a useful tool for studying these lightning flashes. In this study, firstly, based on data acquired by the Lightning Imaging Sensor (LIS) on board the Tropical Rainfall Measuring Mission (TRMM) satellite in the period 1998–2013, the optical radiation characteristics of lightning flashes over the Tibetan Plateau were compared with those over the central and eastern land region (CELR) of China at the same latitude. The results showed that lightning flashes over the Tibetan Plateau had a mean optical radiance of 422.35 μJ sr–1 m–2 nm–1, a mean duration of 210.79 ms and a mean radiation area of 217.33 km2, whereas the lightning flashes over the CELR had a mean optical radiance of 692.83 μJ sr–1 m–2 nm–1, a mean duration of 295.29 ms and a mean radiation area of 290.85 km2. Evidently, lightning flashes over the Tibetan Plateau had significantly lower radiance, shorter life cycles, and smaller radiation areas than those over the CELR. Secondly, the data for lightning events over the Tibetan Plateau acquired from the FY-4A LMI and International Space Station (ISS) LIS were compared from 21 March 2017 to 25 September 2017, and from 20 March 2018 to 18 September 2018. The correlation between the frequency distribution of the optical radiance of lightning events observed by the two lightning imagers was 99.33%, but due to the footprint area of a LMI pixel is larger than that of a LIS pixel, the mean radiance of lightning events over the Tibetan Plateau measured by the FY-4A LMI was only 1/5 of that measured by the ISS LIS. Based on the statistical results, a time/space coincidence window of 2.1 s/33 km was selected. A resulting mean coincidence ratio (CR) of 3.66% was found for the FY-4A LMI and ISS LIS lightning events for the Tibetan Plateau. The spatial distribution of the CR values was correlated with the optical radiance of lightning events and the duration of lightning flashes as well as the number of events in flashes, with the Pearson’s correlation coefficients (r) of 0.80, 0.82 and 0.78, respectively. These results suggest that the optical radiation characteristics of lightning flashes over the Tibetan Plateau have a great impact on their detection by the FY-4A LMI. For observation of lightning flashes over the Tibetan Plateau using the FY-4A LMI, it is necessary to enable the Real-Time Event Processor (RTEP) algorithm to more finely distinguish various regions based on lightning flash characteristics and to set a more flexible and smaller threshold for extracting lightning events.

Development of a cylindrical acoustic lens to control the amplitude and phase characteristics of optical radiation

The promising method of light beam phase control based on beam transmission through the medium layer perturbed with acoustid wave generated by the lateral surface “lens”, requives the exact calculation of the acoustic field inside cylindrical cavity of the “lens”. We use the comm program Comsol for calculation and demonstrate that for the axial symmetric cylinder, which was used as a test object, the calculated distribution very close coinsides with theoretical form resulted from acoustic equations solutions.

Goniometric complex for investigation the optical characteristics of radiation of luminescent structures

In this paper we describe an automated goniometric complex for investigation the optical characteristics and them spatial distribution of luminescent structures.On the market most instruments for measuring of the spatial distribution of radiation are designed for commercial light sources, such as LEDs, incandescent lamps, fluorescent lamps. Often scientific research requires measurements of the spatial distribution of emitted or scattered radiation upon excitation by external laser radiation. Therefore, the device for these measurements was designed and manufactured. In the article the design and principle of operation of the complex are described and its main technical characteristics are presented. During metrological certification specially developed five reference LEDs with different spectral characteristics were used to ensure traceability to the national measurement standards of the Republic of Belarus. The automated goniometric complex allows one to measure the spatial distribution of luminescence and scattering radiation with external laser excitation in the units of the spectral irradiance, luminous flux, chromaticity coordinates and correlated color temperature.The main metrological characteristics of the complex: spectral range — from 396 nm to 753 nm with a spectral resolution of 0.5 nm; power spectral density measurement range — from 3.5∙102 W/m3 to 1∙106 W/m3 in the spectral range from 400 nm to 750 nm with relative combined standard uncertainty of 7.8 %; chromaticity coordinate measurement range for coordinate x from 0.088 to 0.676, for coordinate y — from 0.160 to 0.715, with relative combined standard uncertainty of 5.5 % for coordinate x and 8.4 % for coordinate y; measurement range of correlated color temperature — from 2000 K to 7000 К with relative combined standard uncertainty of 9.3 %; luminous flux measurement range — from 0.6 lm to 35.0 lm with relative combined standard uncertainty of 9.3 %; rotation angle — from minus 90° to plus 90° in tangential direction and from minus 180° to plus 180° in radial direction with angular resolution of 0.5°.Measurement results are processed by specially developed software. Results can be presented in the form of three-dimensional diagrams for selected units of measurement or in form of a text file.

Omnidirectional infrared nonreciprocal absorbers based on CdTe gratings

In this paper, a novel CdTe gratings structure is designed aimed at constructing omnidirectional infrared nonreciprocal absorbers at wavelength from 18 μm to 23 μm. CdTe is a commonly used semiconductor infrared film material, which is widely used in photovoltaic, infrared detection, fluorescence and other applications. The optical radiation characteristics of magneto-optical material CdTe are studied based on the Lorentz-Drude model, which is verified with the optical constants in handbook. The time-domain finite difference (FDTD) method was used to calculate the infrared radiation characteristics of CdTe gratings, and the electric field square modulus distribution with different wavelengths is presented. It is found that the nonreciprocal absorptivity is obvious as the incidence angle is 45° at the positive and negative angles. The effects of magnetic field strength, grating thickness, incidence angles on the optical properties, especially the non-reciprocity are analyzed in details. The numerical simulation results are useful to the thermal radiative design in infrared absorber and other optical instrument.

兆巴压力下蓝宝石发光辐射特性与结构相变

兆巴压力下蓝宝石发光辐射特性与结构相变

Parameters of radiation processes in the microwave resonant plasma

This work presents results of experimental studies of the spectral and photometric characteristics of optical radiation generated by a pulse-periodic microwave discharge close to ECR (2.45 GHz, average power of up to 200 W, argon pressure of 10–4–10–1 Torr). Under these conditions, dense (n e = 1010–4 × 1011 cm–3) low-temperature (T e = 3–5 eV) plasma is produced in the working volume at an ionization rate of 10–3–5 × 10–5. It is shown that the increase in the electron density near the upper boundary of the pressure range at a constant level of the input power leads to a drastic change in the type and spectral composition of plasma radiation and a jumplike increase in the light flux. The results of probe and optical measurements made it possible to determine the range of the operating parameters defining the character and parameters of the radiation processes under study.

Yagi–Uda nanoantenna For NIR domain

Single component metal nanoparticles, such as Ag and Au, have surface plasmon resonance wavelengths in the visible region having a weak dependence on particle size. For double component (core/shell) nanoparticles, by proper tuning the core size and shell thickness, a wide variation in optical radiation characteristics as well as in surface plasmon resonance wavelength up to Near-Infrared (NIR) region can be achieved. These aspects encourage one to model an optical Yagi–Uda antenna adopting core/shell nanoparticles as feed element, reflector and directors. In this paper, adopting the COMSOL Multiphysics software, we design all core/shell Yagi–Uda nanoantennas in the NIR domain. $$\hbox {SiO}_{2}/\hbox {Au}$$ core/shell nanoparticles are taken as antenna elements for the proposed antenna, whose surface plasmon resonance wavelength can be shifted to the NIR region by tuning the core to shell size ratio in a particular size band. The optimized directivity and gain for this antenna is achieved with only one reflector and one director, thus making it ultra-compact, cost-effective and simple in structure. This type of very highly directional Yagi–Uda nanoantenna can be used in medical science such as in targeted drug delivery and in wireless optical communication.

Numerical modelling of radiant energy extinction by water medium containing bubbles and particles of various natures

In the framework of the Mie theory, we developed a numerical model of weakly absorbing medium, containing particles having an arbitrary chemical composition. This model can be applied to the study of the extinction characteristics of the optical radiation by a water layer with gas bubbles or volume-shape particles. The results of the numerical experiment illustrate changes in optical properties of the water due to the presence of bubbles or solid particles. The work displays some calculations of the extinction efficiency factor, the extinction coefficient, and transmission function at visible wavelengths. The influences of concentration and sizes of gas bubbles on the extinction characteristics of optical radiation are illustrated. Features of the extinction of radiant energy are discussed as dependent on a size parameter and a complex index of refraction of scatterers.

Devices of RPC “TENZOR” for investigation of physical environmental factors

The results of multi-year research of Research & Production Company (RPC) “Tenzor” on creating measuring instruments to perform measurements of radiometric and photometric characteristics of optical radiation in the ultraviolet, visible and infrared regions of the spectrum, measurements of microclimate parameters, measurements of noise and vibration metrology equipment are presented. The issue on measuring the luminance of LED sources using a photometer Ecotenzor‑03, illuminance measurement range of which is from 10–2 to 2Ч105 lux, is considered in detail.