GENERATION OF TUNABLE COHERENT FAR-INFRARED WAVES BASED ON BACKWARD OPTICAL PARAMETRIC OSCILLATION IN GALLIUM SELENIDE

We show that it is possible to use backward optical parametric oscilla tion in GaSe to obtain tunable output in the 13-20-mu m range with the minimum threshold intensity as low as a few 10(8) W/cm(2). We may be able to use this configuration to achieve large amplification factors for a coherent weak beam in the far-infrared region. It is also possib le to generate coherent far-infrared waves in the presence of pump and signal waves. (C) 1998 Optical Society of America [S0740-3224(98)0050 5-0].