Optical heterodyne sensor using the Goos–Hänchen shift

A new sensing scheme, capable of measuring various quantities using the Goos-Häanchen shift in the polarization phase domain, is proposed. The phase retardation between s and p polarizations on total reflection is enhanced by using multiple reflections in a plane-parallel transparent plate. This phase shift can be sensitively and stably detected using an in-line heterodyne method. As an application of this method, a displacement sensor utilizing the deflection of a light beam by a lens is developed. This displacement sensor has a resolution of 60 nm over a dynamic range of 120 microm. Good agreement between theoretical and experimental results is shown.