Measurement method of axicon cone angle based on moire fringes of non-diffracting beam

In order to accurately measure the cone angle of an axicon, according to the characteristic that the spacing of the non-diffracting beam concentric annulus did not change with the distance and the amplification characteristic of the moire fringes, a measurement method of the axicon cone angle based on moire fringes of the non-diffracting beam was proposed. When the non-diffracting beams were split and combined by the beam splitter, the moire fringes were formed. Translating the position of one of the beams on the image sensor to realize the change of the moire fringes number, and according to record the center distance under different moire fringes, the axicon cone angle was calculated. The axicon with a cone angle of 0.5° was used as the measured object. Compared with the CMM measurement results, the relative measurement error of the proposed method is approximately 0.54%, and the repeatability is 0.86″, which verify the feasibility of the proposed measurement method of axicon cone angle.