22 June 2015 Point diffraction interferometry based on the use of two pinholes
Author Affiliations +
Abstract
Point diffraction interferometer (PDI) has become the high degree of accuracy device. In the optical wavefront testing the measurement accuracy is much higher than 1.0 nm RMS. In the paper there is presented a new version of PDI with two independently controlled beams using a pinhole plate with two pinholes as a beam coupler instead of a single-mode fiber or single-pinhole plate. Theoretical analysis of the pinhole diffraction wavefront and double pinholes diffraction interference is given. The PDI is used to investigate an interferometer reference lens and compare measurement results. The device can test high NA, the interference is obtained in circularly polarized light, and fringe contrast is adjustable to measure surfaces with different reflectance. The measurement repeatability now has been sub-nm RMS (measured NA = 0.33). The experiment result provides guarantee for the measurement in the high degree of accuracy. In the double pinholes PDI, generating two ideal spherical waves through two pinholes, one wave is as the reference wavefront for interference test, another ideal wavefront is reflected to the pinhole plate by the test mirror, and the tested wavefront and reference wavefront bring interference. Advantages of such arrangement of the PDI are: high maximum numerical aperture (NA = 0.55), distinct fringe patterns of high contrast, high accuracy of surface figure testing and wave-front repeatability RMS error 0.3 nm.
© (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Nikolay B. Voznesenskiy, Nikolay B. Voznesenskiy, Dongmei Ma, Dongmei Ma, Chunshui Jin, Chunshui Jin, Haitao Zhang, Haitao Zhang, Jie Yu, Jie Yu, Mariia Voznesenskaia, Mariia Voznesenskaia, Tatiana Voznesenskaia, Tatiana Voznesenskaia, Wenlong Zhang, Wenlong Zhang, } "Point diffraction interferometry based on the use of two pinholes", Proc. SPIE 9525, Optical Measurement Systems for Industrial Inspection IX, 95251K (22 June 2015); doi: 10.1117/12.2184771; https://doi.org/10.1117/12.2184771
PROCEEDINGS
9 PAGES


SHARE
Back to Top