Tunable IR laser source with optical parametric oscillators in series

A tunable IR laser source is described. A Q-switched Nd:YAG laser at 1.064 µm is used to pump two optical parametric oscillators (OPO's) in series. The first OPO uses a LiNbO(3) crystal and works in the vicinity of degeneracy. Its signal beam (adjusted to 1.82 µm) is used to pump the second OPO, which uses a AgGaSe(2) crystal and covers the range 2.6-6 µm. The conversion efficiency between the energy produced by this OPO in the signal and idler beams (λ(s) = 2.6 µm and λ(i) = 6 µm, respectively) and the input energy at 1.064 µm is 1.75%.