Simulation and analysis of laser beam adaptive focusing using an extended uncooperative target in the loop

A conventional adaptive optics system utilizing a beacon light on or near the target for wavefront sensing is often used to compensate the phase aberrations of laser beam propagating through optically inhomogeneous media. However, there is no such a spatially coherent emitter could be used in most cases, one must rely on the reflection or scattering light from an uncooperative extended target itself to probe the atmosphere channel. In this paper, we show that an incoherent target return could be utilized to adaptively focus a collimated laser beam onto a rough target through atmospheric turbulence by simulation. A laser transmitting and receiver system combined with a wavefront sensorless adaptive optics system based on the modified stochastic parallel gradient descent (SPGD) algorithm simulation platform is established. The results show that all the maximum intensities among 1000 simulations increased and a single localized region of high intensity was achieved 78.7%. Additionally, we verified the system performance at different turbulent strength and discuss these limitations.