Abstract
Using a new experimental geometry, we have proved for the first time that the generation of spatial subharmonic gratings in photorefractive crystals is not dependent on optical nonlinearity. We present results which confirm that the subharmonic gratings result from a parametric excitation of ultra low-frequency eigenmodes of a crystal by a time modulated fundamental grating.
- Received 29 October 1993
DOI:https://doi.org/10.1103/PhysRevLett.73.3082
©1994 American Physical Society