Analysis of stellar interferometers as wave-front sensors

Area of Science:

• Optical Engineering
• Astronomy Instrumentation

Background:

• Accurate wave-front error measurement is crucial for telescope performance.
• Existing methods often rely on derivative calculations, which can be complex.
• Future giant telescopes require advanced cophasing techniques for segmented mirrors.

Purpose of the Study:

• To present an original method for retrieving telescope wave-front errors.
• To evaluate the measurement accuracy of this novel telescope-interferometer.
• To define the practical domain and applications of the proposed method.

Main Methods:

• Theoretical analysis of an original wave-front retrieval principle.
• Combining a telescope's main pupil with a decentered reference optical arm.
• Numerical simulations to estimate measurement accuracy and performance.

Main Results:

• Demonstrated good performance in wave-front error retrieval.
• Identified limitations near the telescope pupil's rim.
• Enabled direct phase evaluation, bypassing derivative calculations.

Conclusions:

• The method offers direct phase evaluation, beneficial for cophasing segmented mirrors in future giant telescopes.
• The technique is suitable for periodic diagnostics of ground- and space-based telescopes.
• Potential applications include real-time observations, such as in extrasolar planet detection instruments.