Tunable mid-infrared source using AgGaSe2

Performance of both an AgGaSe
₂
optical parametric oscillator and amplifier indicate that an efficient source, tunable over the mid-infrared, can be made. AgGaSe
₂
is a very attractive nonlinear material because of its wide range of transparency, high nonlinear coefficient, and nearly ideal phase-matching characteristics. Using annealing techniques, the transmission between about 0.8 to 12.5 μm, can be improved dramatically. The nonlinear coefficient d
₃₆
is high, measured in amplifier experiments to be approximately 39 · 10
^-12
m/V. Phase-matching calculations indicate that by using a 1.7 to 2.1 μm pump, the entire mid-infrared region can be covered with a single-nonlinear crystal. In addition, the birefringence is small enough that the birefringence angle is relatively small and the acceptance angle is relatively large.