Frequency conversion of CO laser radiation in the ZnGeP<Subscript>2</Subscript> nonlinear crystal

The experimental results of the study of CO laser frequency doubling in ZnGeP₂ and GaSe nonlinear crystals of high optical quality are presented. A multifrequency low-pressure Q-switched CO laser and a selective pulsed electroionization mode-locked CO laser with cryogenic cooling were used in the experiments. The highest external factor of radiation conversion into the second harmonic of the pulse-periodic Q-switched CO laser and pulsed mode-locked CO laser was 1% and 3.5%, respectively. Theoretical calculations showed the possibility of obtaining far IR and terahertz radiation using difference frequency generation of CO laser lines in these crystals.     

Tunable middle infrared radiation with HgGa2S4 crystal

Optical properties of orange phased HgGa₂S₄ crystal is investigated. Generation of tunable middle infrared radiation by second harmonic of tunable CO₂ laser radiation has been demonstrated. Second harmonic conversion efficiency with respect to other infrared crystal has also been discussed.     

GaSe<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript><Emphasis Type="Italic">S</Emphasis><Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> solid solutions

The most probable parameters of the pure, doped, and mixed GaSe_1−xS_x (x ≤ 0.4) crystals (solid solutions) are presented together with the results of investigations of their crystal structure and defects, optical and mechanical properties, and damage thresholds. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 35–40, June, 2007.     

Down-Conversion of Short-Wavelength Radiation in LBO Crystal

Russian Physics Journal - Comparative model analysis of the possibilities of down-conversion into the terahertz (THz) frequency range of radiation of all-solid-state femtosecond Ti:Sapphire laser...     

Tellurium and sulfur doped GaSe for mid-IR applications

Centimeter-sized Te:GaSe (??10?mass%) ingots have been grown by the vertical Bridgman technique and studied to reveal the potentials for phase matching and frequency conversion. Less than 5 mass% Te-doped crystals show the hexagonal structure like ??-GaSe. Te:GaSe (??2?mass%) crystals were suitable for non-linear applications. The optimal Te-doping level between 0.1 and 0.5 mass% has been clearly observed in CO₂ laser SHG experiment. The CO₂ laser SHG efficiency in Te:GaSe (0.1?C0.5 mass%) is ??20?% higher than that of GaSe due to better optical quality. Phase matching conditions in Te-doped crystals have been shown to be identical with those of GaSe.     

Model studies of THz-range generation via down conversion of the radiation of Ti:Sapphire lasers in LBO crystals

Results from model studies of the possibility of creating a source of high-power picosecond pulses of terahertz radiation via optical rectification and phase-matched down conversion of femtosecond pulses of Ti:Sapphire lasers in a nonlinear LBO crystal are presented. Modified Sellmeier equations are used in calculations. It is shown that the lengths of coherence for the generation of THz radiation at frequencies higher than 0.5 THz are more than 0.5 mm, allowing the technologically simple production of periodic structures. The maximum length of coherence is achieved for s–s type interactions in the XY plane. Phase-matched s–f type down conversion is possible only in the XY plane, including noncritical spectral matching conditions. Maximum efficiency can be expected for three-wave interactions with the polarization of interacting waves parallel to Z axis.     

Growth of GaSe and GaS single crystals

The paper describes principal manipulations to prepare single crystals of GaSe and GaS. A new simple method of synthesis with single‐zone heating furnace is proposed. Growth of crystals was performed by modified Bridgman method with the use of rotating heat field. Raman and optical depth spectra show high structural and optical quality of obtained crystals. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Cascaded carbon monoxide laser frequency conversion into the 4.3-4.9 μm range in a single ZnGeP2 crystal

Collinear cascaded mid-IR frequency conversion in a single nonlinear optical crystal was accomplished. Concurrent collinear generation of the sum frequency of multiline fundamental band carbon monoxide laser radiation as a first frequency conversion cascade resulted in collinear difference frequency generation within the 4.3 to 4.9 μm spectral range when mixing this sum frequency radiation with the fundamental one as the second cascade in the same ZnGeP(2) nonlinear optical crystal.     

掺杂晶体Cd0.35Hg0.65Ga2S4的光学特性

研究了掺杂非线性晶体Cd0.35Hg0.65Ga2S4的线性和非线性光学特性以及相位匹配.在相同的实验条件下，与已知的中红外晶体相比较，测定了该晶体的损伤阈值.实现了CO2激光二次谐波产生实验，与理论预测相一致. 关键词： 掺杂非线性晶体 Cd0.35Hg0.65Ga2S4 二次谐波产生 CO2激光