Tunable THz source with less than 100 GHz bandwidth

In this work we present results of the optimization of the OPO in terms of output power and spectral linewidth and show results of the THz generation via DFG in DSTMS and OH1. To provide the pump for the DFG process, an optical parametric oscillator (OPO) using KTP crystals as the nonlinear crystal was selected. The KTP crystals are cut at an angle of 64° for type-II phasematching in the xz plane. The pump laser is a Q-switched frequency doubled Nd: YAG laser at 532 nm with pulses of 8 ns and a repetition rate of 100 Hz. Signal waves of around 860 nm are generated and idlers (λι and λ2) in the 1400 nm region.