IDENTIFICATION OF NEAR-INFRARED ABSORPTION-BANDS IN AGGASE2

A comparative investigation of transmission and photoluminescence meas urements has been made on AgGaSe2 single crystals with the emphasis on identifying the origin of the 1.3 mu m and 2.2 mu m nearby absorption bands, which strongly limit the output power and pulse-repetition fre quency of AgGaSe2-based optical parametric oscillators. It is found th at the transition band near 1.3 mu m is due to the donor acceptor (D(0 )A(0)) pair recombination involving the selenium and silver vacancies, while the transition band near 2.2 mu m is related with the nonradiat ive recombination of the precipitates in AgGaSe2.