Phase-matched crystal growth of AgGaSe2 and AgGa1-xInxSe2

AgGaSe2 and AgGa1-xInxSe2 single crystals have been grown by the horizontal gradient freeze technique directly along the phase-matching orientation required for frequency-doubling the output of a 9.27 mu m CO2 laser. Samples for second harmonic generation exceeding 55 mm in length have been fabricated from 19 mm-diameter boules with minimal waste. Low-loss AgGaSe2 samples (after annealing in Ag2Se) generated over 3 W of 4.6 mu m output at external efficiencies of 26%. AgCa1-xInxSe2 crystals were grown with In concentrations between x = 0.37 and 0.42, and were free of the Ga2Se3-rich precipitates that normally plague as-grown AgGaSe2. Non-critically phase-matched second harmonic generation was successfully demonstrated in the sample grown from a melt with x = 0.42. (C) 2000 Elsevier Science B.V. All rights reserved.