Evaluation of the impact of finite-resolution effects on scintillation compensation using two deformable mirrors

The impact of finite-resolution deformable mirrors and wave-front sensors i s evaluated as it applies to full-wave conjugation using two deformable mir rors. The first deformable mirror is fixed conjugate to the pupil, while th e second deformable mirror is at a finite range. The control algorithm to d etermine the mirror commands for the two deformable mirrors is based on a m odification of the sequential generalized projection algorithm. The modific ation of the algorithm allows the incorporation of Gaussian spatial filters into the optimization process to limit the spatial-frequency content appli ed to the two deformable mirrors. Simulation results are presented for imag ing and energy projection scenarios that establish that the optimal spatial filter waist to be applied is equal to the subaperture side length in stro ng turbulence. The effect of varying the subaperture side length is examine d, and it is found that to effect a significant degree of scintillation com pensation, the subapertures, and corresponding spacing between actuators, m ust be much smaller than the coherence length of the input field. (C) 2001 Optical Society of America.