INTERFEROMETER FOR SMALL-ANGLE MEASUREMENT BASED ON TOTAL INTERNAL-REFLECTION

We describe a new method for angle measurement based on the internal-r eflection effect and heterodyne interferometry. A novel prism assembly is designed that can always parallel retroreflect the incoming light beams so the optical configuration is compact. As a differential commo n-path optical configuration is integrated into the design, the linear ity of the method is greatly improved. Details of theoretical analysis of the method and experimental verification of the principle are pres ented. The resolution can be better than 0.3 are sec. The experimental results and further improvements of the proposed method are also addr essed. (C) 1998 Optical Society of America.