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Method for absolute flatness measurement of optical surfaces.
1School of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science and Technology, #200 Xiao-ling-wei, Nanjing 210094, China.
Applied Optics
|May 5, 2009
Summary
A new method uses two optical plates for absolute flatness testing of optical surfaces. This technique requires only one transmission flat, simplifying calibration for large-aperture interferometers.
Area of Science:
- Optical engineering
- Metrology
Background:
- Accurate measurement of optical surface flatness is critical for high-performance optical systems.
- Existing absolute flatness testing methods can be complex and require multiple specialized components.
Purpose of the Study:
- To present a novel, simplified method for determining absolute flatness deviations of optical surfaces.
- To validate the proposed method against established techniques.
Main Methods:
- The method employs two optical plates and four measurements to determine absolute flatness deviations.
- Wavefront error from one plate's inhomogeneity is measured and subtracted.
- Vertical profiles are compared with results from Zygo's three-flat application.
Main Results:
- Absolute flatness deviations for three surfaces were successfully obtained.
- The novel method showed good agreement with Zygo's three-flat application results.
- The technique requires only one transmission flat.
Conclusions:
- The presented two-plate method offers a validated and simplified approach to absolute flatness testing.
- This method is particularly advantageous for calibrating large-aperture interferometers due to its reduced component requirement.
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