Improved growth of AgGaSe2 crystals and phase matched second harmonic generation of 10.6 mu m CO2 laser radiation

Good quality AgGaSe2 single crystal 22 mm in diameter and 80 mm in length i s grown by an improved technique, i.e., descending ampoule with rotation. A lthough the crystals grow with optical defects, postgrowth heat treatment p rocedures are used to successfully eliminate the defects and produce materi al of 62.4% IR transmission at 10.6 mu m. The frequency-doubling device is cut from a cylindrical crystal boule using a new orientation cut method acc ording to the type-1 phase-matched condition. A high optical quality, orien tated AgGaSe2 single crystal of 10 x 10 x 12 mm size is used for second har monic generation (SHG) of the pulsed output of a 10.6 mu m CO2 miniature tr ansversely excited atmospheric laser. A relatively high energy conversion e fficiency of 12% is obtained. It is found that the optical surface damage t hreshold of the crystal is larger than 12 MW/cm(2). (C) 1999 Society of Pho to-Optical Instrumentation Engineers. [S0091-3286(99)00512-7].