High-order correlation technique for imaging through turbulence

TL;DR: In this article, a robust technique for achieving nearly diffraction-limited imaging through the Earth's atmosphere is developed, which makes it possible to approximate the angular Fourier spectrum of any desired object without any recursion procedure for reconstruction of the phase spectrum.

Abstract: A robust technique for achieving nearly diffraction-limited imaging through the Earth’s atmosphere is developed, which makes it possible to approximate the angular Fourier spectrum of any desired object without any recursion procedure for reconstruction of the phase spectrum. The proposed method is based on the fact that the N’th-order spectrum at certain two-dimensional subplanes in (N-1)-dimensional frequency space may be considered as a result of low-pass filtering of the object. It is significant that the filter band becomes much wider than the object frequency band and also that the filter characteristic becomes real with increase in the order N. Undistorted high-order spectra within one of the subplanes can be measured by pupil-plane interferometry technique. Analytical results have been verified by numerical simulation.