[2010] Imaging issues for interferometry with CGH null correctors

Burge, James H., Chunyu Zhao, and Ping Zhou. “Imaging issues for interferometry with CGH null correctors.” Modern Technologies in Space-and Ground-based Telescopes and Instrumentation. Vol. 7739. SPIE, 2010.


Aspheric surfaces, such as telescope mirrors, are commonly measured using interferometry with computer generated hologram (CGH) null correctors. The interferometers can be made with high precision and low noise, and CGHs can control wavefront errors to accuracy approaching 1 nm for difficult aspheric surfaces. However, such optical systems are typically poorly suited for high performance imaging. The aspheric surface must be viewed through a CGH that was intentionally designed to introduce many hundreds of waves of aberration. The imaging aberrations create difficulties for the measurements by coupling both geometric and diffraction effects into the measurement. These issues are explored here, and we show how the use of larger holograms can mitigate these effects.

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