Theoretical Study of Dual-wavelength PPKTP-OPO as a Source of DFG THz-wave

In this paper, we theoretically investigate the dual-wavelength periodically poled KTP optical parametric oscillator (PPKTP-OPO) operating near degeneracy. According to calculation, the dual-wavelength operation can be achieved by quasi-phase matching with a periodically poled structure. The tunable property of the grating period of the PPKTP crystal with temperature tuning determines that, quasi-CW or continuous tunable THz-wave generation can be achieved by difference frequency generation using a dual-wavelength PPKTP-OPO. Compared with a bulk KTP-OPO operating near degeneracy in theory, the gain property of PPKTP OPO is in better performance, contributing to a higher output power of THz generation.