Terahertz generation by DSTMS based on cascaded difference frequency generation

Terahertz (THz) wave generation by organic crystal 4-N, N-dimethylamino-4′-N′-methyl-stilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) with a collinear phase-matching scheme based on cascaded difference frequency generation (DFG) processes is theoretical analyzed. The cascaded Stokes interaction processes and the cascaded anti-Stokes interaction processes are investigated from coupled wave equations. THz intensities and quantum conversion efficiency are calculated. Compared with non-cascaded DFG processes, THz intensities from 17-order cascaded DFG processes are increased to 6.7. The quantum conversion efficiency of 298.5% in cascaded processes can be realized, which exceeds the Manley-Rowe limit.