MIDDLE INFRARED SOLID-STATE LASER DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a middle IR solid-state laser device which is small in size and light in weight, is high in output and stably outputs a middle IR laser beam of a 3 to 5μm band in wavelength. SOLUTION: This middle IR solid-state laser device is characterized by finding that both of conversion efficiency and output characteristics are improved by using an AgGa1-xInxSe2 (x=0.25 to 0.35) crystal as a nonlinear optical crystal. The AgGa1-xInxSe2 crystal is as large asΔθext.L1/2=8.1 deg.cm1/2 in a phase matching permissible angle and isθ=90 deg. in phase matching conditions and therefore its walk off angle (a deviation between exciting light and output light) is zero and the output characteristics with respect to the exciting light are extremely outstanding. Then, if such crystal is used as a nonlinear optical crystal, the need for the angle regulation of the crystal is eliminated and the middle IR coherent light of the 3 to 5μm band of the stable output may be obtained with the high conversion efficiency.