title: Simple theory for degenerate four-wave mixing in photorefractive media.
abstract: A simple analytic theory for degenerate four-wave mixing in photorefractive media is presented. The theory is valid when the backward pump-beam intensity is much smaller than the forward pump-beam and probe-beam intensities.
authors.forename: P M
authors.initials: PM
authors.lastname: Petersen
authors.forename: P M
authors.initials: PM
authors.lastname: Johansen