Abstract

PNP was first proposed as a potentially interesting nonlinear optical crystal by Twieg and Dirk.¹ They reported second- harmonic efficiencies of powdered materials of the order of 160 X urea. But so far, only small (≃0.2- × 0.2- X 0.3-mm³) single crystals of PNP have been grown. Furthermore, the solubility of PNP is too high from isooctane and toluene. In view of the above, PNP warranted a further detailed study. For PNP single crystals to grow and for investigation of nonlinear optical properties in technology, we must first choose suitable solvents and techniques for single crystal growth in bulk. In the present report, the dopant effects on habit of PNP single crystals are studied. We have made an attempt at Nd³⁺, Cd²⁺, Al³⁺, Pr³⁺, and a mixture of Nd³⁺ and Cd²⁺ doping into the solution of PNP. Nd:PNP and Cd:PNP certainly provide single crystals as good as can be obtained. It is assumed that Nd³⁺ solvents influence the mechanism of the growth, giving rise to the formation of less growth defects. Increasing solubility thus will lead to increased growth rate unless other factors interfere with this process.

© 1989 Optical Society of America