Using an incoherent target-return to adaptively focus through atmospheric turbulence

TL;DR

This paper proposes a novel adaptive optics method that uses incoherent target returns and reciprocity principles to focus laser beams through atmospheric turbulence, especially when the target is uncooperative.

Contribution

It introduces a new approach leveraging incoherent returns and reciprocity to adaptively focus laser beams without requiring a cooperative target.

Findings

Simulated adaptive optics system successfully focused through turbulence

Derived a new relation between target and reflected fields

Demonstrated effectiveness with incoherent target returns

Abstract

A laser beam propagating to a remote target through atmospheric turbulence acquires intensity fluctuations. If the target is cooperative and provides a coherent return beam, the phase measured near the beam transmitter and adaptive optics can, in principle, correct these fluctuations. Generally, however, the target is uncooperative. In this case, we show that an incoherent return from the target can be used instead. Using the principle of reciprocity, we derive a novel relation between the field at the target and the reflected field at a detector. We simulate an adaptive optics system that utilizes this relation to focus a beam through atmospheric turbulence onto the incoherent surface.