SINGLE-CRYSTAL GROWTH AND CHARACTERIZATION OF A NEW ORGANIC NONLINEAR-OPTICAL MATERIAL - -(4'-ACETYLPHENYL)-1,4-DIOXA-8-AZASPIRO[4.5]DECANE(APDA)

-(4'-Acetylphenyl)-1,4-dioxa-8-azaspiro[4.5]decane (APDA) was found to be a new organic material for nonlinear optical devices. Prior to its application to devices, material purification, single crystal growth, characterization and optical properties were studied, and second harm onic generation from the grown single crystal was demonstrated. Recrys tallization from ethyl acetate solution by slow cooling, zone refining and sublimation under reduced pressure were explored. Among them, a c ombination of recrystallization and sublimation was the most effective for APDA purification. Single crystals were grown by the Bridgman tec hnique with different growth parameters for the furnace temperature, t he growing rate and the cooling rate of grown crystals. Single crystal s with a diameter larger than 12 mm and length of 28 mm were obtained from the melt, but had some cracks. Characterization, measurements of optical properties of APDA crystals and second harmonic generation dem onstration revealed that the crystals had good quality suitable for ap plication to nonlinear optical devices, for example, frequency doubler s of laser diodes in the blue region.