Wavefront sensorless multi-conjugate adaptive optics for imaging in deep atmospheric turbulence: preliminary numerical analysis

Abstract

This paper deals with the problem of imaging in deep atmospheric turbulence conditions such as the ones encountered in long near-horizontal propagation scenarios. Under such conditions, anisoplanatism as well as the presence of intensity scintillations prevent efficient use of conventional single-wavefront corrector adaptive optics systems. Multi-conjugate adaptive optics (MCAO) techniques have been successfully demonstrated in the field of astronomy to mitigate anisoplanatism effects and improve correction on extended objects in weak atmospheric turbulence conditions. However these techniques typically require the use of several wavefront sensors which increases system complexity, and are impacted by the presence of intensity scintillations. We propose to use a wavefront sensorless MCAO method based solely on the optimization of image quality metrics. In this method, the commands applied to the deformable mirrors are computed from a metric derived directly from the compensated image. The method has the advantage of being more robust to scintillations and does not require wavefront sensors. In this preliminary numerical study, we evaluate the benefit of the MCAO approach in deep turbulence.