Space charge fields: a fringe technique for observing such fields during hologram writing in LiNbO_3

Abstract
An interference fringe method is reported that allows rapid monitoring of the large scale (nonsinusoidal) space charge field which develops during hologram writing with nonuniform light intensity in LiNbO3. This large scale field is distinct from the sinusoidal space charge fields that constitute the hologram. The large scale field has been shown elsewhere to be important in that it affects the efficiency of hologram writing and leads to history effects. Using the fringe method, a dielectric breakdown process associated with the large scale field was observed which may have been responsible for some effects reported by Carlsen in his work on computer applications.