Widely tunable infrared (5.5-11.2 /spl mu/m) difference frequency generation in LiInS/sub 2/

The first demonstration, to the best of our knowledge, of continuous-wave (cw) difference-frequency generation in LiInS/sub 2/ crystal is reported. Two Ar/sup +/ laser-pumped Ti:sapphire lasers were employed as widely tunable pump sources. With a total input power intensity of /spl sim/5 kW/cm/sup 2/, DFG power of 33.5 nW was produced at 7 /spl mu/m, which yielded a power conversion efficiency of about 1 /spl mu/W/(W/sup 2/.cm), and an estimated effective nonlinear coefficient d/sub eff/ of 4.17 pm/V.