Widely tunable and monochromatic terahertz difference frequency generation with organic crystal DSTMS

Widely tunable and monochromatic terahertz (THz) difference frequency generation with organic crystal DSTMS was investigated experimentally. A double-pass KTiOPO4 optical parametric oscillator, pumped by a frequency-doubled Nd:YAG laser, was employed as the source of 1.3-1.6 µm dual wavelength. The THz tuning spectrum covered a range of 0.88−19.27 THz. The dependence of the THz output on the crystal thickness and pump wavelength was studied. The results were well explained based on theoretical calculations. With a pump energy of 2.47 mJ, the output energy reached 85.3 nJ/pulse at 3.80 THz, which corresponded to a peak power of 17.9 W and photon conversion efficiency of 3.6‰