SPIE Proceedings [SPIE SPIE LASE - San Francisco, California, USA (Saturday 2 February 2013)] Nonlinear Frequency Generation and Conversion: Materials, Devices, and Applications XII - Second-harmonic generation in Hg 0.35 Cd 0.65 Ga 2 S 4 and Hg 0.52 Cd 0.48 Ga 2 S 4