Frequency-agile coherent tunable THz-wave generation from 1.5 to 60 THz using Galvano controlled KTP-OPO

The THz region is well-matched to the low-frequency motions of molecules. THz pulsed imaging and spectroscopy are powerful tools for exploring biological, chemical, pharmaceutical fields. For these purposes, we developed a widely tunable and frequency-agile monochromatic THz source spanning from 1.5 to 60 THz, using nonlinear optical processes. By using the organic crystal 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST), we succeeded in the generation of THz-wave tunable of broad spectrum (1.5~47 THz). In addition to, 30~60 THz was also generated by using a semiconductor crystal ZnGeP₂ (ZGP) with large output of ~mJ order. In these experiments, we used frequency-agile KTP-OPO pumping source controlled by a Galvano-scanner.