Photorefractive delay line for the visualization and processing of time-dependent signals

We present an optical time-delay line based on photorefractive beam coupling in a rotating crystal. The delay line can be tapped continuously or at selected positions.We demonstrate a 64-channel device with a BaTiO(3) crystal rotating at 1.5 rpm, which gives approximately a 167-Hz bandwidth and 0.5 s of time delay for each channel.