The use of modified hill-climbing algorithm for laser beam focusing through the turbid medium

摘要

We investigate the ability to focus the laser beam (λ=0.65 μm) propagated through the scattering suspension of polystyrene microspheres in distilled water by means of bimorph deformable mirror. Shack-Hartmann sensor was used to measure the local slopes of the Poynting vector, while the CCD camera was used to measure the intensity of the focal spot in the far-field. Bimorph deformable mirror with 14 electrodes was applied in order to increase the intensity of the focal spot in the far-field. We investigated the efficiency of the laser beam focusing improvement by means of three techniques: LSQ fit-error minimization by Shack-Hartmann sensor, Hill-climbing optimization by Shack-Hartmann sensor and Hill-climbing optimization by far-field CCD camera.