Adaptive-optics correction of a stellar interferometer with a single pyramid wave-front sensor

Area of Science:

• Astronomy
• Optical Engineering
• Adaptive Optics

Background:

• Stellar interferometers require precise wave-front correction for high-resolution imaging.
• Traditional methods often use multiple sensors, increasing complexity and cost.
• Differential piston errors significantly degrade interferometric performance.

Purpose of the Study:

• To investigate a single pyramid wave-front sensor for closed-loop reconstruction of stellar interferometer wave fronts.
• To assess the sensor's capability to measure aberrations and differential piston simultaneously.
• To evaluate the performance of adaptive optics with this sensor for astronomical applications.

Main Methods:

• A refractive-square-based pyramid sensor was placed in the combined focal plane of a stellar interferometer.
• The sensor's signals were analyzed to reconstruct wave-front aberrations and differential piston.
• Numerical simulations were performed for the Large Binocular Telescope to assess adaptive optics loop performance.

Main Results:

• The single pyramid sensor successfully reconstructs wave fronts on both apertures, including differential piston.
• Simulations for the Large Binocular Telescope demonstrate effective differential piston rejection.
• Atmospheric correction with differential piston compensation is possible when the Strehl ratio exceeds 20%.

Conclusions:

• A single pyramid wave-front sensor offers a viable solution for simultaneous wave-front and differential piston measurement in stellar interferometers.
• This approach enhances adaptive optics system efficiency and performance.
• The method is effective for atmospheric correction in large ground-based telescopes.