High-Quality Organic 4-Dimethylamino-N-methyl-4-stilbazolium Tosylate (DAST) Crystals for THz Wave Generation

Using the Slope Nucleation Method (SNM) and highly purified materials along with an optimized growth program, we produced high-quality organic 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) crystals. The growth method greatly improved crystallinity. The difference frequency mixing, based on the KTiOPO 4 (KTP)-optical parametric oscillator (OPO), generated a coherent, tunable, THz wave in the range of 2 to 30 THz using DAST crystals. These superior DAST crystals also extended the THz generation time. We achieved a constant THz energy output for over 10 h, whereas conventional DAST crystals had reduced the THz wave output in less than 1 hour. We anticipate increased use of DAST crystals for THz generation because of superior performance.