Growth and characterization of DAST crystal with large-thickness

• The large-thickness of the DAST crystal was obtained in the present work.
• New surface morphology was observed on the (001) face of the crystal.
• The etched morphology of the both faces of (001) and (001¯) was characterized.
• The dielectric constants and the dielectric loss were tested from 50 Hz to 500 KHz.

Highly nonlinear optical 4-N, N-dimethylamino-4-N-methyl stilbazolium tosylate (DAST) crystals with large surface and thickness was grown by the slope nucleation technology with slow-cooling in a high concentration solution. The structure and composition of the crystal were confirmed by X-ray diffraction (XRD). The surface morphology of the crystal was characterized by optical microscope. Growth layers were observed on the (001) surface and several isolated “island layers” were also found. The mechanism of crystal growth was analyzed. Etching behavior of the (001) and (001¯) faces of the crystal was studied with methanol, respectively. Optical properties of the crystal were also characterized by UV–vis–NIR spectrometer. The dielectric constants and the dielectric loss were tested by impedance analyzer.