Electro-Optic Measurement Using High-Quality 4-dimethylamino-N-methyl-4-stilbazolium Tosylate (DAST) Crystal

We evaluated the electro-optic (EO) properties of 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) crystals by external EO probing. The EO signal power obtained from the DAST crystal increased by 8 dB compared to that obtained from the KTiOPO 4 (KTP) crystal at 90 kHz. The larger EO signal power obtained from the DAST crystal was almost constant at low frequencies (30 Hz to 90 kHz), whereas the KTP crystal could not respond below 180 Hz. We also observed excellent signals at all measured points due to the high crystallinity of the crystal grown by the slope nucleation method (SNM).