Fig. 1. Growth device of DAST crystal by spontaneous nucleation method

Fig. 2. Experimental setup of THz radiation source based on DAST crystal via different frequency generation

Fig. 3. Photographs of DAST crystal. (a) Mass concentration is 3.0 g/100mL, size is (4×3.5×0.35) mm³; (b) mass concentration is 3.5 g/100 mL, size is (4×4×0.38) mm³; (c) mass concentration is 4.0 g/100 mL, size is (4.5×3.5×0.4) mm³

Fig. 4. Microscopic images of the (001) plane of DAST crystal. (a) Mass concentration is 3.0 g/100 mL;(b) mass concentration is 3.5 g/100 mL; (c) mass concentration is 4.0 g/100 mL

Fig. 5. Raman spectrum of DAST crystal

Fig. 6. Output performance of KTP-OPO. (a) Relationship between phase-matching angle of KTP-OPO and the output wavelength of signal light and idle light; (b) relationship between voltage of optical scanner and the output wavelength of signal light; (3) dual wavelength pump light output characteristic of KTP-OPO; (4) dual-wavelength tunability characteristic of KTP-OPO

Fig. 7. Broadband THz output spectrum based on DAST crystal