Experimental study on measurement of aspheric surface shape with complementary annular subaperture interferometric...

Area of Science:

• Optical metrology
• Surface characterization
• Interferometry

Background:

• Annular subaperture reconstruction algorithms offer potential for testing complex optical surfaces.
• Previous work established a Zernike annular polynomial and matrix-based algorithm.
• Experimental validation is crucial for practical application.

Purpose of the Study:

• To experimentally demonstrate and validate a previously developed annular subaperture reconstruction algorithm.
• To compare the accuracy of the annular subaperture method with a classical auto-collimation technique.
• To explore the algorithm's limitations and potential for characterizing higher spatial frequencies.

Main Methods:

• Complementary annular subaperture interferometry was employed to test a parabolic mirror.
• The experimental results were compared against measurements obtained using the classical auto-collimation method.
• Analysis involved characterizing measurement data using finite Zernike coefficients.

Main Results:

• The annular subaperture method demonstrated good agreement with the auto-collimation measurement results.
• The study identified limitations related to finite Zernike coefficients for data characterization.
• The possibility of characterizing higher spatial frequencies with sufficient Zernike coefficients was shown.

Conclusions:

• The complementary annular subaperture interferometric method provides accurate surface shape measurements for parabolic mirrors.
• The algorithm shows promise for extension to testing large concave aspheric mirrors with acceptable accuracy.
• Further refinement of Zernike coefficient utilization can enhance the characterization of spatial frequencies.