Shanghai Institute of Optics and Fine Mechanics has made progress in the research of interferometer wavefront calibration methods

Recently, the research team of the High end Optoelectronic Equipment Department at the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, has made progress in the study of wavefront calibration methods for interferometer testing. The relevant research results were published in Optics Express under the title of "High precision wavefront correction method ininterometer testing".

High precision optical components have been fully applied in fields such as laser technology, optical communication, medical imaging, astronomy and space exploration, semiconductor manufacturing, and scientific research. The use of interferometers is currently the main method for high-precision optical detection. In order to obtain the true surface shape error of the test component, the wavefront calibration method must be used to calibrate the wavefront error of the interferometer test. However, there is currently no complete method for wavefront calibration in optical processing.

Figure 1. Ring error generation

Figure 2. Results of Ring Error Repair

In this work, the research team proposed a new high-precision optical surface wavefront correction method to address the difference between wavefront error in Fizeau interferometer testing and actual surface error. The main content includes fitting optical surface function parameters, correcting lateral distortion, eliminating misalignment errors, and calculating concave surface errors. And the error of this method was analyzed in depth from the aspects of function parameter fitting, ray tracing, interpolation, etc. The wavefront calibration of the off-axis parabolic mirror in the zero position test configuration proves the effectiveness of this method. The results showed that the circular error generated by the experiment was significantly reduced, and the off-axis error increased from 0.23 λ to 0.05 λ (λ=632.8nm). The PV deviation from the non spherical surface exceeded 8.5mm. This study is of great significance in the high-precision optical component detection process.

Source: Shanghai Institute of Optics and Fine Mechanics