Abstract

Optical damage (laser induced changes in the index of refraction) in ferro­electric materials such as lithium niobate has severely limited their usefulness in optical devices¹. The physical basis of this effect, which causes a collimated laser beam in a damaged crystal to diverge², is not yet fully understood. In an attempt to gain further insight into this problem, we have developed a new electrostatic technique for probing the damaged areas³. This technique has allowed us: 1) to observe directly the macroscopic charge separation which is associated with the damage⁴, 2) to determine the charge distribution from the measured potential distribution, 3) to demonstrate that one of the proposed models⁵ is inconsistent with the data, 4) to propose an explanation of optical clean-up⁶, and 5) to discover a new source of optical damage which is associated with pyroelectricity⁷.

© 1978 Optical Society of America