High-Quality Organic 4-Dimethylamino-N-Methyl-4-Stilbazolium Tosylate (DAST) Crystal for Electro-Optic Measurement

Hiroaki ADACHI  Kazuaki NAGAOKA  Fumi TSUNESADA  Masashi YOSHIMURA  Yusuke MORI  Takatomo SASAKI  Ai-ichiro SASAKI  Tadao NAGATSUMA  Yuta OCHIAI  Noboru FUKASAKU  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E86-C   No.7   pp.1352-1358
Publication Date: 2003/07/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Recent Progress in Microwave and Millimeter-wave Photonics Technologies)
Category: Measurements Techniques
Keyword: 
DAST,  organic crystal,  electro-optic,  electric-field sensor,  

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Summary: 
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.