By using KDP crystals as nonlinear material, the Nd-glass laser beam of wavelength 1.06 μm is converted into its second harmonic wave of wavelength 0.53 μm. KDP single crystals are grown in the crystal growing system which utilizes the fact the solubility of KDP in water decreases markedly with temperature. Power variation of second harmonic wave by varying the incident angle of the laser beam near the phase matching angle is investigated by photographic densitometry method. The obtained FWHM is 0.36˚ for 1.28 cm path length in KDP crystal. Also the variation of phase matching angle with the temperature of crystal is investigated. The obtained value is 0.0025-0.0051˚/℃ with KDP. This agrees with the theoretically obtained value, 0.0039˚/℃.
