Influence of Thermal Annealing on Terahertz Dielectric Properties of ZnGeP2 Crystals

Russian Physics Journal - The influence of thermal annealing on the dielectric properties of ZnGeP2 crystals in the terahertz frequency range is studied by terahertz time domain spectroscopy. The...     

Effect of Post-Growth Treatments on the ZnGeP2 Single Crystal Optical Properties in THz Range

Russian Physics Journal -     

Investigation of the Process of Optical Damage of ZnGeP2 Crystals Using Digital Holography

Russian Physics Journal - A method of visualization of the process of optical damage of a ZnGeP2 single crystal using digital holography is suggested. The mechanism of the ZnGeP2 single crystal...     

Diagnostics of Inclusions in ZnGeP2 Crystals by the Method of Terahertz Spectroscopy

Russian Physics Journal - Results of experimental investigations of the dispersion of the refractive index n(ν) and of the absorption coefficient α(ν) of a ZnGeP2 crystal in the...     

Conditions of Phase Matching for the Second Harmonic Generation with ZnGeP2 Crystals

The reasons for the discrepancy between the available experimental data on the phase-matching conditions for the second harmonic generation with nonlinear ZnGeP₂ crystals are elucidated. The calculated and experimental phase-matching angles agree for crystals at room temperature and low pumping radiation power. Simultaneous solution of the consistent shortened equations for the complex amplitudes and of the heat conductivity equation demonstrates that pumping by intense laser beams causes the angles phase-matching to decrease by 5–25° and the long-wavelength edge of phase matching for doubled frequency of CO₂-laser radiation to increase from 10.32 to 10.8 m. An excess decrease in the angles phase-matching by 1–3° is due to the asymmetry of the thermal processes caused by the birefringence.     

Influence of Parameters of Optical Fibers on Optical Soliton Interactions

The interaction between optical solitons is of great significance for studying interaction between light and matter and development of all-optical devices, and is conducive to the design of integrated optical path. Optical soliton interactions for the nonlinear Schr¨odinger equation are investigated to improve the communication quality and system integration. Solutions of the equation are derived and used to analyze the interaction of two solitons.Some suggestions are put forward to weaken their...     

Influence of the Pseudopotential Nonlocality on the Calculated Optical Characteristics of Crystals

The standard procedure used to calculate the optical characteristics of crystals is the replacement of the coordinate operator, which is not well defined in the case of infinite periodic systems, by the momentum operator. This is correct only for the local potential, and in general, the replacement leads to the occurrence of the velocity operator. In the present study, the influence of the appropriate corrections, analyzed previously by other researchers only for atoms, is examined for optical spectra of a wide class of crystals.     

Influence of Thermal Cycling on the Optical Spectra of TlInS2 Crystals Having an Incommensurate Phase

The crystals of TlInS₂ are investigated by the methods of optical absorption and second-harmonic generation. It is found that after a crystal is cooled for the first time an additional band appears in the absorption spectrum and the intensity of the second harmonic is greatest at temperatures 170–201 K. The characteristic features of the spectra and their dependence on the process of thermal cycling are explained by the formation of clusters and regions of an incommensurate phase in a commensurate one.     

Influence of a Magnetic Field on the Nonlinear Optical Susceptibility of NiI2-Doped CdI2 Single Crystals

The influence of treatment in a magnetic field at low temperatures on the nonlinear optical properties of NiI₂-doped CdI₂ single crystals is investigated. The impurity ions in the interlayer space or more complex centers into which these ions enter can align on exposure to a magnetic field due to the interaction with the membrane vibrations of the lattice and create residual polarization in a specimen. This polarization causes redistribution of the electric charge on the bonds and improves the nonlinear optical properties of single crystals.     

Influence of Postgrowth Processing Technology on the Laser Induced Damage Threshold of ZnGeP2 Single Crystal

Russian Physics Journal - The laser induced damage thresholds of ZnGeP2 single crystals are determined. The values of the thresholds under the action of laser radiation at a wavelength of 2,097...     

The Influence of Dimensional Parameters of DAST Nanocrystals on Their Linear and Nonlinear Optical Parameters

Optics and Spectroscopy - Nonlinear optical trans-4'-(dimethylamino)-N-methyl-4-stilbazolium tosylate (DATS) nanocrystals are synthesized in polymethylmethacrylate by nucleation in a drying...     

介质球掺杂导致的无序效应对光子晶体光学性能的影响

采用自组装法制备了聚苯乙烯(PS)微球三维光子晶体结构,通过在PS微球悬浮液中掺入不同浓度的二氧化硅大球,实现了光子晶体结构从有序向无序过程的转变。通过对这些样品的透射、反射进行测量和分析,发现无序效应对光子晶体的光子响应特性具有极大的影响,随着无序程度的增加,高频波段的透射率急剧下降,低频波段的法布里-珀罗振荡消失,光子带隙蓝移且逐渐消失;而在掺杂浓度为0.02%(质量分数)时,光子晶体带隙中心的最低透射率从10%下降到1%,且反射单峰随着探测角度的增大而分裂为双峰。这有助于基于介质球三维光子晶体沿Γ-L方向透射消光,促进其在新型光学器件领域的应用发展。     

二氧化硅蛋白石光子晶体中粒子重构对光学性质的影响

使用自组装法制备了蛋白石结构二氧化硅纳米球三维光子晶体,并对样品在150,300,450℃温度下进行了热处理.随热处理温度的升高,光子晶体禁带中心波长出现22.5 nm的蓝移,且禁带宽度变窄.对于在450℃热处理的样品,其测量的禁带中心波长为572.5 nm,与理论计算结果有较大差异.引起样品光学特性变化的原因是热处理...     

An Investigation of the Influence of Secondary Optical Elements on the Output Parameters of Photovoltaic Modules

Technical Physics - Secondary optical concentrators (focons) designed to operate in a solar concentrator photovoltaic module with Fresnel lenses have been developed and investigated. Both...     

Optical Properties of a Nanocrystalline Co-Doped TiO2 after Various Treatments

Physics of the Solid State - The absorption spectra of cobalt-doped anatase TiO2 nanopowders in the infrared and visible ranges have been studied after various oxidative and reductive treatments....     

Preparation and properties of epitaxial ZnGeP2 films

Thermodynamic analysis has been applied to the vapor over a ZnGeP₂ crystal when the chlorine source is provided by ZnCl₂. ZnGeP₂ film growth has been examined and the electrophysical and photoluminescence parameters have been measured. All these autoepitaxial films have the chalcopyrite structure, while those parameters are determined by the defects and the substrate orientation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 74–78, April, 1988.We are indebted to L. G. Lavrent'eva for interest, to A. I. Gribenyukov and T. E. Tkachenko for assistance in growing the single crystal; and to F. Kim for the microprobe analysis.