Control of structured light beams focusing through anisotropic multiple-scattering media via multi-focus-based digital optical phase conjugation

A framework to focus structured light beams through a multiple scattering medium (MSM) with the full vector transmission matrix (VTM)-based digital optical phase conjugation (DOPC) is proposed. According to the DOPC principle, the required input field composed of two orthogonally linear polarization components can be calculated by the measured full VTM combined with a well-designed target field. Then the input field is encoded into a double-channel computer generated hologram displayed on a vector spatial light modulator to shape and control the polarization, amplitude and phase of the light before and after the MSM respectively. And the desired output field composed of several discrete focal spots can be obtained through the MSM. We demonstrate experimentally the feasibility of our method through several examples: generation of vector beams, array vector beams and vortex beams. We also demonstrate numerically the generation of clear optical vortex ring with high peak to background ratio through the MSM using our method. These results show that our method provides an effective way to control and optimize structured light beams focusing through the MSM.