Nd:YAG pumped nanosecond optical parametric oscillator based on LiInSe2 with tunability extending from 4.7 to 8.7 μm

LiInSe2 is one of the few (only 5) non-oxide nonlinear optical crystals whose band-gap (2.86 eV) and transparency allowed in the past nanosecond optical parametric oscillation in the mid-IR without two-photon absorption for a pump wavelength of 1064 nm. However, the first such demonstration was limited to the 3.3-3.78 mu m range for the idler and the average idler power did not exceed 2.5 mW. Here we report broadly tunable operation, from 4.7 to 8.7 mu m, of an OPO based on LiInSe2, achieving maximum idler pulse energy of 282 mu J at similar to 6.5 mu m, at a repetition rate of 100 Hz (similar to 28 mW of average power). (C) 2009 Optical Society of America