Heat treatment and its effects on the optical quality of AgGaSe2 single crystals

The heat treatment of AgGaSe2 has been studied on the basis of the microphase diagram and differential thermal analysis results. The effect of heat treatment on the optical quality of the crystal has also been investigated. It is found that both quenching and annealing treatments could improve the optical quality of the crystal, but annealing of AgGaSe2 in presence of Ag2Se at 800 degrees C is more effective. After the heat treatment, the IR absorption and frequency doubling efficiency are improved considerably. An energy conversion efficiency of 8.2% has been obtained in the frequency doubling of a CO2 laser at 10.6 mu m with the annealed AgGaSe2 crystal.