Measuring Method of Radius of Curvature Based on Dual-Frequency Laser Interferometer

Abstract

In order to achieve high-accuracy measurement of radius of curvature of optical sphere, ultra-high accuracy radius of curvature testing device is developed by dual-frequency laser interferometer and Fizeau interferometer based on cat's eye and confocal method. Through analyzing the error source models of radius of curvature testing, optical configuration of the testing device has been optimized. Precise environment control and real-time monitoring system is also established to reduce the errors caused by environment. Through the above processes, the radius of curvature measurement relative accuracy is better than 2 ppm. One optical sphere, R88.5 mm, test aperture 59 mm, has been tested. Testing result is 88499.465 ± 0.176 μm, meeting the design requirement. The method has high accuracy and practical advantages.

Study of a high-precision displacement sensor based on a configured moving light field with uniform scanning

“…The second kind of motion, also called natural traveling waves, can obtain highly accurate periodic motion, but it is easily affected by the external environment and it is usually very expensive for precise measurement. For example, the cost of a dual-frequency laser interferometer is very high and it is easily disturbed by the external environment [28]. The third kind of motion is an equivalent motion synthesized by field intensity, which has the characteristics of low cost, high accuracy, and strong anti-interference.…”