Energy Of Optical Radiation Research Articles

High-temperature test of tin-lithium CPS under deuterium plasma irradiation conditions

This paper is devoted to experiments on testing of the Sn-Li capillary porous system (CPS) under conditions of deuterium plasma irradiation, carried out at a plasma-beam installation (PBI). As a metal CPS matrix, molybdenum mesh was used. The paper presents a detailed description of the development of technology and procedure for the fabrication of the investigated sample, intended for plasma testing, as well as experiments on irradiation of Sn-Li CPS with deuterium plasma. As a result of the experiments performed, the dependences of the temperature of the investigated sample on the energy of the plasma contacting with the CPS, time dependence of the gas phase composition in the PBI chamber during irradiation of Sn-Li CPS with deuterium plasma, optical spectra depending on the temperature were obtained. Post-experimental material science studies with a sample of Sn-Li CPS were also performed and the results of microstructure, thermal and X-ray phase analysis were obtained. Analysis of the experimental data obtained showed that the energy of deuterium plasma precipitated on the Sn-Li alloy is re-emitted into the energy of optical radiation on the evaporating neutral atoms of lithium and tin. A complete evaporation of the alloy from CPS, during interacting with deuterium plasma, leads to partial destruction of the metal matrix of molybdenum.

Experimental study of dynamics and soft X-ray emission of laser produced plasma from low-density foam Ti targets

Low-density foam targets are expected to be good candidates for efficient laser produced plasma (LPP) and soft X-ray (SXR) sources due to the less energetic debris compared with solid targets. Three Ti targets with different densities were irradiated by a pulsed Nd:YAG laser in vacuum. The average ion energy and the time-of-flight (TOF) peak voltage decreased as the Ti target density decreased. Furthermore, the differences among the three Ti targets increased with increasing laser intensity. The average ion energy of low-density foam Ti targets had a slightly weaker angular dependence compared with solid Ti targets. The plasma plume optical images illustrated that solid Ti plasma expanded faster in the direction of laser incidence with stronger anisotropy compared to foam Ti plasma. In addition, the optical radiation intensity integrated from a wavelength region of 200–850 nm of plasma plume increased with decreasing initial target density, which indicated that more absorbed laser energy was converted to plasma optical radiation energy (internal energy) instead of ion kinetic energy for targets with lower initial densities. The SXR radiation had no significant difference among the three Ti targets. These results demonstrate that appropriately reducing the initial target density can significantly reduce kinetic energy of ion debris without affecting the SXR radiation output.

Simulations of single-mode laser emission along a waveguide connected to cross-coupled microresonators

ObjectiveSingle-mode operation is very important for laser emissivity; to exceed the emissivity of a single laser, the phase locking of all lasers in an array can be achieved only when the laser array is coupled and operated in single-mode. MethodsIn this study, a single-mode laser emitted along the waveguide was realized through cross-coupling microspheres connected to a straight waveguide. Whispering-gallery modes were formed at the equators of the two microspheres when their resonance conditions were simultaneously satisfied. Compared with a single microcavity, the FSR of the coupled microcavities was significantly increased owing to the Vernier effect. Moreover, when the waveguide was coupled with the microspheres in the weak field of the resonance modes, the whispering-gallery modes near the equator were significantly suppressed, and a new quadrilateral mode was formed. ResultThe energy in the coupling microspheres was concentrated in the stable quadrilateral mode and the Q factor was high (∼104). The single-mode laser energy in the waveguide accounted for 82 % of the total optical radiation energy of the device. This work has application prospects in laser switches and on-chip light sources.

THE RESULTS OF EXPERIMENTAL STUDIES OF THE PASSAGE OF LIGHT ENERGY UNDER THE SKIN OF ANIMALS ALONG INDIVIDUAL HAIRS

This paper presents new scientific results of experimental studies that refute the generally accepted fact that the coat solely protects animals from the effects of solar energy. The purpose of this study was to confirm the fact of the spread of optical radiation energy under the animal’s skin along individual hairs, as light guides. The authors of this study experimentally determined the optically conductive structure of an individual wool hair, the components of the transmission parameter of an individual wool hair, namely the coefficient of light transmission inside the wool hair, the coefficient of attenuation of internal light transmission by the substance of the wool hair, the coefficient of losses in the middle of the cylinder of the wool hair due to the beam scattered in the internal structure and the refractive index of its outer shell. Based on the use of methods of photometry and geometric optics, theoretically substantiated and experimentally obtained results regarding the establishment of a mathematical dependence of the total amount of optical radiation energy entering the hair cylinder on the value of the angle of incidence of the beam on the surface of the hair, the cleanliness of the inner core of the cylinder structure, the length of the light-conducting section to the surface of the skin, as well as the refractive index of its outer shell. Based on the results of experimental studies, mathematical dependencies were obtained that describe the spectral light-conducting properties of an individual hair, as well as the distribution of energy emitted in the thickness of the skin along the entire length from the point of penetration into the hair and to the follicle – the place of use of optical energy in photobiological processes. The obtained results of experimental studies of the passage of optical radiation energy along the length of a single hair into the body of an animal are of practical importance for photobiologists investigating the effect of optical radiation from the Sun on biological objects of animal origin.

Simulation and design of dual-band quantum dot infrared photodetector based on metal grating structure

Quantum dot infrared photodetectors (QDIP) have a weak ability to capture light, which limits the further improvement of absorptivity to a certain extent. Since the localized surface plasmon resonance (LSPR) can effectively couple the optical radiation energy and result in a significant field enhancement effect in the near-field range, it is introduced to improve the absorptivity of the QDIP. Concretely, the strip metal grating structure is coupled to the active region of the traditional QDIP, and a metal reflective layer is added at the bottom of the QDIP to improve the absorptivity by using the metal–semiconductor–metal structure. The simulation results show that the addition of the optimized strip metal grating structure can make the photon absorptivity of QDIP reach more than 90% in both frequency bands of 37.5 and 48.5 THz, and the coupling characteristics of LSPR are studied by the analysis of the electric field distribution of QDIP, which can provide the theoretical guidance for the combination of metal grating and traditional QDIP.

Synthesis and Photoluminescence of Nanostructures Based on Zinc, Cadmium, and Manganese Sulfides in a Polyacrylate Matrix

The photoluminescence of nanostructures based on zinc, cadmium, and manganese sulfides is studied in relation to the conditions of synthesis and doping in a (poly)methyl methacrylate (PMMA) medium. Photoluminescence excitation is defined by interband electronic transitions in the semiconductor structure, by the absorption of optical radiation energy at structural defects in the crystals, and by energy transfer to the excited energy levels of Mn2+ ions. The luminescence signal results from recombination processes at the levels of structural defects mainly at the surface of particles and from 4T1 → 6A1 electronic transitions between the intrinsic energy levels of Mn2+ ions. Based on variations observed in the photoluminescence and photoluminescence excitation spectra of PMMA/(Zn, Cd, Mn)S composites, some inferences about the structure of the particles are made. It is shown that their photoluminescence is influenced by the distribution of Mn2+ ions in the structure of the layers and at the surface of particles.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ РАСПРОСТРАНЕНИЯ ПУЧКОВ ЛАЗЕРНОГО ИЗЛУЧЕНИЯ В НЕРАВНОВЕСНОЙ ДВИЖУЩЕЙСЯ ОБЛУЧАЕМОЙ НЕЙТРОНАМИ ПЫЛЕВОЙ ПЛАЗМЕ, СОДЕРЖАЩЕЙ НАНОЧАСТИЦЫ УРАНА

The use of uranium nanoparticles dispersed in a laser-active medium instead of traditionally used methods of heterogeneous nuclear pumping of active gas medium can increase the fraction of energy carried by fission fragments from the condensed phase into the gas medium by more than an order of magnitude. This creates the conditions for increasing the efficiency of nuclear into optical radiation energy conversion. However, the scattering and absorption of laser radiation by an active medium containing uranium nanoparticles are important factors preventing the laser radiation generation in such a medium. Mathematical modeling of the generation and amplification of laser radiation in a moving spatially inhomogeneous nuclear-excited neutron-irradiated argon-xenon medium containing uranium nanoparticles injected into a cylindrical laser-active dusty element, taking into account optical inhomogeneities caused by the dust component. The process of amplification and intensity distribution of a master oscillator laser beam in a moving spatially inhomogeneous nuclear-excited argon-xenon neutron-irradiated medium containing uranium nanoparticles has been studied for the first time. Data were also obtained on the propagation of a light beam near a relatively sharp dust component concentration decrease in moving gas medium. As a brief result: moving spatially inhomogeneous nuclear-excited neutron-irradiated argon-xenon medium containing uranium nanoparticles does not have a pronounced destructive effect on the propagation of laser radiation in it, on condition that the light flux is not wider than the dust component.

Синтез и фотолюминесценция наноразмерных структур на основе сульфидов цинка, кадмия и марганца в полиакрилатной матрице

Photoluminescence of nanoscale structures based on zinc, cadmium and manganese sulfides depending on the conditions of synthesis and doping in the medium (poly)methylmethacrylate (PMMA). Photoluminescence excitation is associated with interband transitions of electrons in the semiconductor structures, absorption of optical radiation energy by defects in the crystal structure, as well as with the transfer of energy to the excited energy levels of Mn2+ ions. Luminescence occurs as a result of recombination processes at the levels of defects in the structure of the surface of particles and 4T1 → 6A1 transitions between the proper energy levels of Mn2+ ions. Based on changes in the photoluminescence spectra and photoluminescence excitation of PMMA/(Zn,Cd,Mn)S compositions, assumptions are made about the structure of particles. It is shown that their photoluminescence is affected by the distribution of Mn2+ ions in the structure of layers and on the surface of particles.

Features of an Electromagnetic Field Generated by Interaction between High-Energy Electrons and a Solid Medium with Allowance for Secondary Processes

A way of calculating the angular distribution of changes in the energy of optical radiation generated by high-energy electrons passing through a solid transparent body is proposed that allows for the contribution from secondary electrons. The values are found of the angles at which peaks in optical radiation are observed when electrons pass through mica and glass.

Calibration of Radiation Sources and Detectors Over a Broad Range of Measurement of the Energy of Optical Radiation

A method of calibration of devices used to measure energy by means of a calorimeter and reference photodiode is described. Experimental results of the calibration are presented. Through the use of the method, energy meters, photodetector devices, and radiation sources may be calibrated over a range more than 108 times the measured radiant energy with the use of time conversion.

Solution of the problem of impact elastoplastic deformation of a thin layer of mechanoluminophor using the methods of the dislocation microdynamic theory of plasticity

The paper presents the results of numerical simulation of the output optical signals of mechanoluminescent shock sensors. Such sensors operate on the principle of direct conversion of mechanical impact energy into optical radiation energy. The sensing element of such a sensor is a thin layer of phosphor enclosed between two transparent flexible polymer films. The mathematical model of the sensor is based on the process of excitation of the glow centers (activator atoms) in a strong electric field of a moving dislocation. The stress-strain state of the film sensing element under quasi-static uniaxial loading under the action of a single pressure pulse is considered. The analysis of constitutive equations for elasto-plastic deformations and the basic equations of the dynamic theory of dislocations. To calculate the deformation of the sensing element, a microscopic model of an isotropic elastic-plastic medium with hardening is used, according to which the plastic deformation is considered as a result of the movement and multiplication of dislocations, and the hardening is as a result of their partial locking due to the increased density.

МЕТОДЫ ПОВЫШЕНИЯ ЭФФЕКТИВНОСТИ И НАДЕЖНОСТИ ИЗЛУЧАЮЩИХ ДИОДОВ НА ОСНОВЕ GaInAsP

The quantum production of the electroluminescence of semiconductor emitters of the optical range is determined by the parameters of several stages of the process of converting electrical energy into optical radiation energy. To improve the efficiency and stability of the emitting diodes, the losses at certain stages of this process were investigated. When obtaining information on the distribution of impurities in p–n junctions of light-emitting diodes, volt-farad characteristics were measured. In the studied radiators, a linear impurity distribution in the p – n junction was obtained. The electrical and electroluminescent characteristics of emitting diodes based on GaInAsP were studied. The elucidation of the mechanism of diode degradation during their current training for 3000 hours at different current densities and temperatures, on the radiation intensity, that measured at low and high injection levels, on the value of the photocurrent p-n-junction and on their electrical characteristics was carried. It is shown that the degradation of the studied radiators is due to the change in the ratio between the radiative and non-radiative components of the current in p-n-junctions, as well as the change in the electron lifetime in the active region of the heterostructures. The kinetics of degradation of diodes is explained by the drift of charged defects in an electric field. It was found that a decrease in the quantum efficiency of GaInAsP-based diodes with a decrease in the injection level is due to the presence of local narrowing of p-n-junctions. It is shown that in order to reduce degradation of emitting diodes and to increase their quantum efficiency at low injection levels, it is necessary to reduce the concentration of residual impurities and lattice defects in the used semiconductor heterostructures.

Comparison of optical spectral devices in the framework of system approach

In the framework of solving the problem of comparison and evaluation problem of the spectral devices performance and quality two methods of optical spectra measurement are considered: by using diffraction grating spectral device and multichannel optical spectrometer. Comparison has been performed based on the matrix representation of the measuring results of the optical radiation energy spectrum by each device. Complex and power spectrum spread functions are obtained. Parameters of spectral devices which are defined its spectral resolution are established.

Enhanced optical transmission of composite subwavelength rectangular-hole array based on metal silver thin-film

Metal nanostructures can effectively couple the optical radiation energy in free space to a highly confined surface mode due to the excitation of surface plasmons (SPs), resulting in a greatly enhanced local field in the nanoscale range of the metal surface, it’s great significance for the collection and excitation of broadband light. In order to achieve the broadband and high transmittance of metal nanostructures, a composite rectangular-hole array metal micro/nano structure was designed in this paper, and the transmission characteristics of the structure were studied by using the finite difference time domain (FDTD). The results showed that compared with the single hole array, the compound hole structure has many advantages, such as optical field enhancement, tenability and so on, and there are multiple transmission peaks in the transmission spectrum. In addition, we discussed the effects of the length and width of the rectangular holes on the light transmission characteristics of the structure array. For example, with the increase of the length b of the rectangular hole, the maximum transmittance of the structure increases from 79.7% to 88.3%, and corresponding to the central peak increases from 526 nm to 611 nm. Both the transmission bandwidth and transmittance are improved. While the change of the length a of the rectangular hole produces a peculiar multi-peak phenomenon, the analysis shows that when the length a of the rectangular hole is 250 nm, the maximum transmittance of the full symmetric composite rectangular hole array can reach up to 93% and the FWHM of the transmission peak is 354 nm, much larger than the 80 nm proposed in ref. [27] , so the frequency selectivity will be enhanced in the design of the filter. At the same time, the effect of the side length D of the center square hole on the transmission characteristics of the structure array is also discussed. The results of our research have certain guiding significance for the development of enhanced optical transmission theory and application value in the fields of novel optical sensors, t filter and optical transparent electrode.

Light source for measurement of threshold power and energy of optical radiation

We describe a light source to provide calibrated radiance in a device for verifying the threshold characteristics of optical systems employing detector arrays. We investigate a variety of approaches to light-source calibration and estimate the measurement error of the device.

Mathematical simulation of kinetic processes in moving irradiated by neutrons gas medium containing uranium nanoparticles

The theoretical model and program complex for mathematical simulation of processes of transformation the nuclear energy into optical radiation energy was developed. The model includes the equations of gas dynamics, as well as the equations describing the kinetic processes in the non-equilibrium plasma excited by uranium fission fragments.The kinetic processes in the moving irradiated by neutrons argon-xenon gas medium containing uranium nanoparticles was investigated.The space-time evolution of this medium in nonuniform changing over time neutron field was studied. The space-time evolution of the gas parameters (temperature, density, velocity, pressure), as well as the distribution of the concentration of uranium nanoparticles under different initial velocities of the gas and the size of the nanoparticles was calculated.The amplifying properties of a laser-active space-nonuniform nuclear-excited moving argon–xenon medium, containing uranium nanoparticles and irradiated by neutrons, was studied.

Study of processes of nuclear reaction energy conversion into energy of optical radiation

This paper presents the preliminary results of the reactor experiments to study the spectral-luminescent properties of gaseous mixtures (based on He, Ne and Kr noble gases). The investigated gaseous mixtures were excited by the products of 6Li(n,α)3H nuclear reaction. The IVG.1M research reactor acted as a source of thermal neutrons. The description of experimental facility and experimental ampoule device for reactor irradiation is presented. The highest intensity of radiation was observed in experiments with He-Ne gaseous mixture on lines with a wavelength of 585.2 nm, 640.4 nm and 703.4 nm. He-Ne mixture’s main energy in the range of 500 nm to 800 nm was radiated on atomic transitions 3p-3s of neon. The most intensive transitions in neon were 3p’[1/2]0 - 3s’[1/2]10 with λ = 585 nm and 3p[1/2]1 - 3s’[1/2]20 and 3s[3/2]10 with λ = 703.4 nm and 724 nm.

Development of the reactor lithium ampoule device for research of spectral-luminescent characteristics of nuclear-excited plasma

This paper describes the development procedure of the reactor ampoule device to perform the experiments on study of spectral luminescence characteristics of nuclear-excited plasma formed by products of 6Li(n,α)3H reaction under neutron irradiation at the IVG.1 M research reactor.The methods of nuclear reactions’ energy conversion into the energy of optical radiation of nuclear-excited plasma are presented. A scheme of reactor experiments, the experimental facility and experimental device to carry out the reactor experiments are considered in paper. The designed ampoule device is totally meets the requirements of irradiation experiments on the IVG.1M reactor.

Application of Optical Spectrophotometry for Analysis of Radiation Spectrum Emitted by Electric Arc in the Air

This paper presents the results of measurement and analysis of optical radiation emitted by a free burning electric arc. The aim was to determine the application possibilities of optical spectrophotometry for detection of electric arcs. The research works considered electric arc generated with a constant voltage supply between two copper electrodes in the air, carried out under laboratory conditions. A high resolution optical spectrophotometer was used for registration of optical radiation. The analyses involved determination of two dimensionless descriptors obtained for the gathered spectra. Moreover, for each of the registered intensity distributions, the energy values were calculated for three frequency ranges. Based on the measured signals, the possibility of application of spectrophotometry for the optical radiation analysis was confirmed. The analysis indicated that the most energy of optical radiation is detected for the range of 200–780 nm, while above 780 nm almost no optical energy is emitted. Spectrophotometric studies performed in the UV-NIR range are of interest since one can obtain information about the structural defects (at lower wavebands) or impurities and/or point defects (at low energies bands). It was also stated that the obtained descriptors may be applied for diagnosis and identification of electric arc purposes.

Radioluminescence of solid neodymium-doped laser materials excited by α-particles and fission fragments

The characteristics of radioluminescence of Nd3+ : Y3Al5O12 crystals and laser glasses under excitation by plutonium-239 (239Pu) α-particles, as well as by α-particles and spontaneous fission fragments of californium-252 (252Cf), are studied. The radioluminescence branching ratios βij for the transition from the 2F25/2 level to the 2S+1LJ levels in Nd3+ : Y3Al5O12 crystals are measured. Radioluminescence from the 2P3/2 level to low-lying levels is observed. The βij ratios for transitions from the high-lying 2F25/2, 4D3/2, and 2P3/2 levels are theoretically calculated. The lifetimes of metastable levels of Nd3+ excited by 252Cf fission fragments are measured. The efficiency of the conversion of energy of α-particlesand fission fragments to the energy of optical radiation of Nd3+ : Y3Al5O12 crystals and laser glasses is determined.