Optically controlled Fabry-Perot interferometer using a liquid crystal light valve

We report an optically controlled Fabry-Perot interferometer which uses a liquid crystal light valve (LCLV) for one of the mirrors. The light valve rotates the plane of polarization for light incident on its read side through an angle dependent on the intensity of a write beam incident on its other side. The Fabry-Perot interferometer is constructed using a polarizing cube beam-splitter and a second mirror. The finesse of this Fabry-Perot varies sharply with the rotation angle introduced by the LCLV. The dependence of this rotation angle on the incident write beam intensity varies with the frequency of the voltage applied to the LCLV, the bias voltage, and the orientation angle of the LCLV. Experimental performance is examined using a single mode He-Ne laser beam and compares well with theoretical predictions: This device has potential uses in optical computing and optical neural networks.