Testing of large-aperture aspheric mirrors using a single coated lens

Area of Science:

• Optical Engineering
• Metrology
• Surface Measurement

Background:

• Measuring aspheric surfaces is complex and difficult.
• Existing methods may lack precision for large-aperture components.

Purpose of the Study:

• To propose a novel optical system for measuring large-aperture aspheric surfaces.
• To achieve high-precision null compensation in optical metrology.

Main Methods:

• An optical system with a single coated lens was designed.
• The first surface of the compensator acts as an auto-collimation surface.
• Initial parameters were derived using third-order aberration theory and optimized numerically.

Main Results:

• The system effectively measures large-aperture aspheric convex/concave surfaces.
• A measurement accuracy of 0.0063λ rms was achieved for an oblate spheroid (426 mm aperture).
• High-precision null compensation was realized.

Conclusions:

• The proposed optical system offers a viable solution for precise measurement of large aspheric surfaces.
• This method enhances accuracy and efficiency in optical metrology for challenging surface forms.