Ground-based stellar interferometry with adaptive optics

A ground-based optical interferometer appears to be a powerful research tool to measure the high angular resolution astrophysics parameters and synthesize the high resolution astronomical images. However, the fringe visibility sensitivity of the ground-based stellar interferometer with large aperture telescope is often degraded by atmospheric turbulence. To enhance the fringe visibility sensitivity, adaptive optics is considered as a promising technology to solve the atmospheric turbulence issue for a ground-based stellar interferometer with large size apertures.

In this dissertation, we developed the appropriate theoretical foundations and methodologies to evaluate the visibility sensitivity for a ground-based stellar interferometer with adaptive optics and also built a novel secondary adaptive optics testbed in the laboratory. The method using the Strehl ratio to estimate the mean square coherence loss factor is introduced. A novel adaptive optics testbed which has the capability to compensate tip-tilt effect and higher order phase aberration is described. The characteristics and performance evaluation of the adaptive optics system are also presented. The time response of the adaptive optics testbed is approximately 6.8 ms. Our experimental results indicate a 5.5dB phase-aberration compensation gain for a diffraction limited telescope with adaptive optics when D / r 0 = 1.7571. Using this experimental result, we calculate an 11dB phase-aberration compensation gain for a stellar interferometer with adaptive optics for the same D / r 0 . A conclusion, future works and adaptive optics system design recommendations for MRO interferometer are included.