Serial transform optical correlator design principles.

Optical correlators such as the 4f and VanderLugt optical systems have been an active area of research for many years; we refer to these types of optical system collectively as serial transform correlators (STCs). Despite being well known, misconceptions regarding the design of STCs are not uncommon. We show, for example, that one correlator configuration reported to suffer from a phase curvature problem in fact works correctly. We present and prove a simple set of rules to follow in the selection of a STC design that does not contain unnecessary constraints and that makes it easier to identify permissible optical systems. As examples, we discuss three representative types of correlator configuration, one of which is discussed in detail to highlight its practical advantages. A novel proof of the design rules is presented that does not depend on details such as what lenses or combination of lenses are used, what their focal lengths are, or what their locations are within the optical system. We also present a conventional Fourier optics proof.

Alignment layers for improved surface-stabilized ferroelectric liquid-crystal devices.

Ultrathin silane monolayer and silicon oxide alignment layers in surface-stabilized ferroelectric liquidcrystal devices are shown to enhance bistability and reduce degradation from ions.

Stochastic noise in TEM(00) laser beam position.

The centroid of a single-transverse-mode laser beam fluctuates in position because of spontaneous emission of the laser medium into higher transverse cavity modes.

Squeezing of classical noise by nondegenerate four-wave mixing in an optical fiber.

Nondegenerate four-wave mixing in an optical fiber is shown to attenuate one quadrature of random sideband fluctuations created by external modulators. A theory of the nonlinear interaction that includes nonlinear dispersion fits the results. Analogous experiments on quantum noise inputs should prove successful.