Non-imaging method for angle measurement based on an axicon

Abstract

A new non-imaging angle measurement method based on an axicon is proposed in this paper. This method uses an axicon that can form a complex light spot with a clear edge and rich feature information after total internal reflection and refraction on the sloped face compared with convergent lenses, which can only form a blurry edge spot. According to the high sensitivity of the beam transformation of the axicon to the incident angle, light spot images with obvious feature variation can be easily obtained to achieve angle measurement with high accuracy. The method based on an axicon can meet the application requirements of multiple angle measurement ranges, and the structure is simple and compact. In the small-angle measurement experiment combined with a telescope module, the measurement resolution can reach 1′′, the mean absolute error is 0.0010°, and the relative error is within 0.25% in the measurement range of 1.6°.