Shape Controlled Crystal Growth of Organic Nonlinear Optical Material DAST

Muneo YOSHIDA, Kyoji KOMATSU*, Shinji ONODERA and Toshikuni KAINO

Institute for Chemical Reaction Science, Tohoku University; 2-1-1 Katahira, Aoba-ku, Sendai-shi 980-8577 Japan

In recent years, organic nonlinear optical materials have become of considerable interest for potential applications in optoelectronics. An organic salt 4-(4-dimethylaminostyryl)-1-methylpyridinium tosylate (DAST) crystal has extremely large optical nonlinearities and is a promising material for optical switching and frequency conversion. DAST crystal grown in b direction with sufficient length is necessary to utilize the largest electro-optic coefficient r11 and the crystal should take waveguide structure in order to fabricate highly efficient optical devices.
In methanol solution, growth rate of [100] direction of DAST crystal is faster than that of [-100] direction and growth rate of [001] direction is faster than that of [00-1] direction. In this paper, crystal growth from a seed crystal was performed by temperature lowering method and the crystal with ridge structure parallel to b axis was grown successfully by using a substrate with a grooved structure and applying the growth behavior of the crystal.

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