Enhanced picosecond terahertz wave generation based on cascade effects in a terahertz parametric generator

Enhanced terahertz wave generation via a Stokes cascade process has been demonstrated using picosecond pulse pumped terahertz parametric generation at 1 kHz repetition rate. Clear cascade saturation of terahertz output was observed, and the corresponding cascade-Stokes spectra were analyzed. The maximum terahertz wave average power was 22 μW under a pump power of 30 W, whereas the maximum power conversion efficiency was 8 × 10⁻⁷ under a pump power of 21 W. The THz power fluctuation was measured to be about 1% in 20 min. This THz parametric source with a relatively stable output is suitable for a variety of practical applications.