16-MU-M INFRARED GENERATION BY DIFFERENCE-FREQUENCY MIXING IN DIFFUSION-BONDED-STACKED GAAS

Tunable 90-ps 15.6-17.6-mu m coherent radiation was generated by means of difference-frequency mixing in diffusion-bonded-stacked GaAs. The sample consisted of 24 alternately rotated layers with a total length of 6 mm and with low optical loss to achieve third-order quasi-phase m atching. The wavelength-tuning curve was close to the theoretical pred iction, demonstrating that the bonding process maintained nonlinear op tical phase matching over the entire interaction length. Maximum conve rsion efficiency of 0.7%, or 5% internal quantum efficiency, was measu red at 16.6 mu m, consistent with the theoretical predictions. (C) 199 8 Optical Society of America.