Chapter VI ferroelectric and piezoelectric materials

On the basis of work published in 1963, two trends appear to be taking place: a lessening of interest, particularly in the Russian literature, in barium titanate and other perovskites; and a great increase in interest, particularly in this country, in electro-optic properties. The latter is caused by two recent developments, the use of electro-optic crystals for modulating Laser beams, and the discovery (1961) of frequency doubling of coherent light in piezoelectric crystals. Frequency doubling has now been reported in NH 4 H 2 PO 4 (ADP), NaClO 3 , NaBrO 3 , quartz, tourmaline, CdS, CdSe, InSb, GaAs, and elemental Te, as well as a variety of ferroelectric crystals. In view of the concentrated interest, papers concerning optical harmonics and electro-optic modulation (but not basic measurements) have been collected in a single section.