Optical properties of 4-N,N-dimethylamino-4^′-N^′-methyl-stilbazolium 2,4,6-trimethylbenzenesulfonate crystals at terahertz frequencies

We have measured the optical properties of 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS), a highly nonlinear organic crystal, in the terahertz (THz) spectral range. The conditions for efficient THz pulse generation through optical rectification of near-infrared pulses have been calculated and confirmed experimentally. The results show that DSTMS as a source of THz radiation is superior to 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST), a well-investigated nonlinear material with one of the highest nonlinear susceptibilities known so far.