Simultaneous SRS and SHG in lithium iodate

This report summarizes the results of a study of the simultaneous occurrence of stimulated Raman scattering (SRS), second-harmonic generation (SHG), and sum-frequency generation (SFG) in lithium iodate. The simultaneous occurrence of these processes in lithium iodate results in selectable, multiple outputs spanning the 0.54 to 0.65 micrometer region of the visible spectrum. The SRS/SHG/SFG device consists of a lithium iodate crystal placed inside a cw-pumped, repetitively Q-switched Nd:YAlO3 laser. Two-mirror and three-mirror versions of the SRS/SHG/SFG device were studied. The two-mirror SRS/SHG/SFG average power outputs that were achieved were 0.54 (1.13 W), 0.565 (78 mW), 0.592 (685 mW), 0.622 (98 mW), and 0.655 micrometers (107 mW). The three-mirror SRS/SHG/SFG outputs were 0.54 (950 mW), 0.565 (218 mW), 0.592 (202 mW), 0.622 (29 mW), and 0.655 micrometers (26 mW). Pulses obtained from the two-mirror setup were approximately 25 to 40 ns long; pulses obtained from the three-mirror setup were 4 to 10 ns long. Experimental and analytical studies were also carried out concerning interactions which occur between the simultaneous SRS, SHG, and SFG processes.