Optical second harmonic generation in crystals of organic dyes

The technique developed by Kurtz and Perry (1) to examine frequency doubling in powders was used to survey approximately 100 organic dye powders for second harmonic generation. Six new optically nonlinear materials were found. One of these dyes, a member of the family of coumarin dyes, 7-diethylamino-4-methylcoumarin, appears to be at least as good a frequency doubler as LiNbO3. In addition, its resistance to surface damage is much higher than that of LiNbO3and so it may prove to be a useful material.