Abstract
Calculating the influence matrix between surface error and wavefront aberration is a key step in the Ritchey-Common test. A method that uses unit-excitation operation to calculate the influence matrix with high accuracy was studied in order to improve the precision of the test. It retrieves the system wavefront aberration when the flat mirror concludes only one kind of Zernike aberration, and obtains the influence coefficient vector through Zernike fitting. The influence matrix is formed from the coefficient vectors of all the Zernike aberrations. Least square fitting is then used to reconstruct the surface shape of the tested mirror. After reconstructing the wavefront with Ritchey angles of 26.5° and 40.5°, the test results show PV and RMS values of 0.1413λ and 0.0194λ respectively for the Φ90 mm flat mirror. Compared to the results from direct testing, the PV and RMS error in the Ritchey-Common method are 0.0828λ and 0.0109λ, respectively. This method can calculate the influence matrix accurately, eliminate the dependence on the big F-number in traditional influence matrix methods and can reconstruct the surface shape with high precision.
| Original language | English |
|---|---|
| Pages (from-to) | 771-777 |
| Number of pages | 7 |
| Journal | Guangxue Jingmi Gongcheng/Optics and Precision Engineering |
| Volume | 26 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 1 Apr 2018 |
| Externally published | Yes |
Keywords
- Numerical calculation
- Optical inspection
- Ritchey-Common method
- Unit-excitation method
- Zernike fitting