All Solid-state Tunable Optical Parametric Generator Theoretical And Experimental Study

By virtue of broadening the spectrum of laser output wavelength, the optical parametric generator as a tunable and coherent light source, has been widely used in the fields of spectroscopy, medicine, scientific research, and military affairs. Along with the development of nonlinear material processing technology and laser technology, optical parametric generators, oscillators and amplifiers have been more and more varied in kinds, efficient in conversion, and largely used in scope. In particular, the middle infrared optical parametric oscillator in the infrared wave band safe to human eyes has entered the phase of actual use.The author of this dissertation has done some theoretical and experimental research work on temperature tuning QPM OPO and OPG which are supported by Henan province key science and technology attack plan and fund project (0223024900). This dissertation not only analyzes and calculates the physical mechanisms, tuning methods, and acceptance bandwidths of the optical parametric generator from a theoretical approach, but also acquires the wide infrared tunable parametric light output of the all solid state temperature tuning PPMgLN optical parametric generators and oscillators pumped by the 1064nm laser, after having conducted experimental research on pump source of optical parametric generators.The dissertation features the following points of main content. First, it conducts the formula deduction, analysis and numerical calculations of the tuning characters and tuning rates of four tuning modes of the quasi-phase matching optical parametric generators, namely, angle tuning, pump wavelength tuning, grating period tuning, and temperature tuning. The formula for calculating tuning rates and the curves are obtained respectively. Second, it conducts the formula deduction, analysis and numerical calculations of the acceptance bandwidths for period, temperature, angle of incidence, pump wavelength and the output parametric spectrum. The formula for calculating acceptance bandwidths and the curves are obtained respectively. Third, it conducts theoretical research on optical parametric oscillator of the crystal angle tuning. On the basis of the cases of signal-resonanted OPO and idler-resonanted OPO, the dissertation deduces and calculates the relationship between the output signal wavelength and the tuning angle, as well as the acceptance bandwidth for the angle and tuning rate of rotation angle of the crystal, with which to further analyze and compare signal-resonanted OPO with idler-resonanted OPO. The approximate formula in paraxial approximation and the curves are obtained respectively. Fourth, it conducts the formula deduction, analysis and numerical calculations of the noncollinear quasi-phase matching gains and the output parametric spectrum, which leads to the conclusions that under the same circumstances, the gains of noncollinear interaction will be much less than those of the collinear interaction, and consequently the noncollinear interaction possesses the larger acceptance bandwidths than that of the collinear interaction. The precise formula and the curve for calculating output signal spectrum are obtained respectively. Fifth, the pump source for the optical parametric generator is studied theoretically and experimentally. On the basis of detailed research on the characteristics of Q-switched laser, the 1064nm acousto-optically Q-switched Nd: YAG laser is selected as the pump source of the OPG Last but not the least, the defect of low damage threshold of the conventional periodically poled crystal is overcome. Widely and continuously tunable OPO and OPG are obtained and a temperature tuning optical parametric generator based on PPMgLN prototype is obtained. The project was highly appraised in November 2005 by famous experts and won the first prize for Henan province's information industry scientific and technical payoffs in 2006.