Segmented mirror phasing using the focal-plane intensity.

Area of Science:

• Optics and Astronomy
• Telescope Engineering
• Phase Measurement Techniques

Background:

• Segmented primary mirrors in telescopes can suffer from piston phase errors.
• Accurate phase retrieval is crucial for optimal telescope imaging performance.

Purpose of the Study:

• To develop a robust method for subaperture piston phase retrieval in telescopes with segmented primary mirrors.
• To demonstrate the effectiveness of the developed method using simulations.

Main Methods:

• A novel phasor-based error function is constructed using the optical transfer function (OTF).
• Iterative algorithms utilizing error gradients are employed for piston phase retrieval.
• Simulations incorporate photon-noise-limited conditions and phase diversity for validation.

Main Results:

• The method simplifies optical transfer function calculations at specific spatial frequencies.
• Simulations with 18 hexagonal subapertures show unique and accurate piston retrievals.
• Phase diversity significantly enhances the accuracy and uniqueness of the retrieved piston phases.

Conclusions:

• The developed phasor-based method offers an effective approach for subaperture piston phase retrieval.
• The technique is particularly useful for telescopes with segmented primary mirrors.
• Simulated results confirm the method's accuracy and robustness, especially with phase diversity.