Simple measurement of a wedge angle based on subwavelength grating

Abstract

In this study, a high-precision and low-cost instrument was developed for the measurement of the wedge angle of wedge plates. The module was designed using two prism-patterned subwavelength gratings, with the −1 order rays extracted using a semiconductor laser beam-splitting device. Subsequently, in reference to Snell’s Law and the diffractive characteristic, the wedge angles of wedge plates were tested and analyzed when the two points on the movable receiving screen were overlapped through adjustment of the distance. This result revealed that the proposed system achieved sub-second ultimate resolution for the wedge angles of the wedge plate under a 1-µm precision requirement for measuring instruments.