We present a new method called the slope nucleation method (SNM) for the growth of high-quality organic 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) crystals. The SNM features the ability to control the nucleation position and the growth orientation of DAST crystals in spontaneous nucleated growth. X-ray diffraction (XRD) rocking curve measurements indicate that the SNM is effective for obtaining high-quality DAST crystals as compared to conventional spontaneous nucleation methods. We evaluated the electro-optic (EO) properties of DAST crystals by an external EO probing technique because DAST crystals are expected to be used in transverse-field probing. DAST crystals exhibits nearly five-times EO sensitivity enhancement as compared to inorganic KTiOPO4 (KTP) crystals 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 improved crystallinity of the crystal grown by the SNM.

This paper describes blue second harmonic generation (SHG) by an organic crystal of 2-furyl methacrylic anhydride (FMA). It has short cut-off wavelength of 380 nm and SHG coefficients at 1064 nm. d3324 pm/V and d3116 pm/V. In 900 nm region 90-degree phase-matched blue SHG is observed using a Ti: Sapphire laser as a fundamental source. This crystal is not hygroscopic and does not exhibit sublimation at room temperature. Fine polishing is also possible.