Abstract

We demonstrate a single-beam interferometer which effectively subtracts an exponentially weighted history of the input from the current value, thus functioning as a novelty filter. The filter uses signal depletion by photorefractive amplification of noise (fanout). Input which is stationary for longer than the photorefractive response time is strongly depleted, but any portions of the Input which change their phase, amplitude, wavelength, or polarization are immediately transmitted.

© 1988 Optical Society of America