A NEW GROWTH METHOD FOR LONG ROD-LIKE ORGANIC NONLINEAR-OPTICAL CRYSTALS WITH PHASE-MATCHED DIRECTION

A novel crystal growth technique called indirect laser-heated pedestal growth (ILHPG) is proposed for growth of organic crystal. The main ad vantage of the ILHPG method is that a long rod-like organic crystal ca n be grown in any crystal direction. This advantage is effective for s econd-order nonlinear optical crystals because the high efficiency of wavelength conversion can be attained by a long nonlinear optical crys tal with a phase-matched direction. We applied the method to the cryst al growth of 2-adamanthylamino-5-nitropyridine (AANP) which has large second-order optical nonlinearity. AANP crystals with length of more t han 20 mm and diameters ranging from 300 mu m to 2 mm have been grown. In addition, it has been experimentally confirmed that the efficiency of second harmonic generation for the long rod-like AANP crystal grow n by ILHPG is higher than that for the conventional AANP crystal grown by the Bridgman-Stockbarger method because of longer interaction leng th of the ILHPG-grown crystal.