Angle measurement based on the internal-reflection effect and the use of right-angle prisms

A new development in angle measurement based on the internal-reflection effect (AMIRE) is described in which a pair of right-angle prisms is used to replace the previously used elongated critical-angle prisms, resulting in lower costs and a more compact size. Excellent linearity is achieved through careful alignment of the right-angle prisms. The measurement sensitivity and range can be selected through the use of light sources with different polarization states. Experiments with a prototype sensor demonstrated a measurement range of 1.6°, a resolution of 0.04 arcsec, and a nonlinearity error of ±0.1%. Both analytical and experimental results are presented.