Determination of the frequency interval of phase-matched nonlinear conversion in powders of various molecular crystals

Frequency doubling in various powders of molecular crystals was investigated using a tunable laser utilizing F₂⁺ centers in LiF. The dependence of the converted radiation intensity on the pump frequency was used to determine the frequency interval where nonlinear phase-matched conversion can be achieved and the noncritical (90°) phase-matching frequency.