Light Field Regulation And Imaging Research Of Disordered Media

The multiple scattering of light in disordered media severely disturbs the phase and amplitude information of the outgoing light field,and the irregular speckle field generated greatly restricts the ability to use light waves for imaging and information transmission through such media.However,research shows that the original information carried by the light field is not lost and can be extracted from the scattered field by means of light field modulation methods.Therefore,the development of a set of light field modulation technology suitable for strong scattering environment is of great significance for expanding the application fields of optical detection,identification and information transmission.This thesis systematically studies the light field modulation schemes in the scattering system from three different routes.Under the premise of a linear scattering system,these solutions have been experimentally proven to have stable and significant effects in light refocusing or imaging applications.The main contents are as follows:1.The feedback optimization technique without the prior information of the scattering environment is studied.Based on the linear invariance and superposition of the light field,a sequence optimization algorithm and a global search algorithm are introduced to verify the focusing effect experimentally and analyze the influencing factors.2.The wavefront shaping method based on the principle of optical phase conjugation is studied.Based on the time inversion symmetry of the scattering system,the scattered light wavefront is detected and shaped to achieve fast focusing of the scattered light,and then the optical memory effect is used to extend the imaging of the point light source into a range of imaging to achieve real-time imaging through disordered media.3.The transmission matrix method is studied.The transmission matrix is measured to obtain the complete information of the scattering system,and the solution of the input modulation phase is abstracted as a phase recovery problem.A new light field modulation method combined with GSW(weighted Gerchberg-Saxton)algorithm is proposed and implemented.The algorithm uses the transmission matrix and its transformation as the system transmission operator.Iteratively transforms between the input and output surfaces and applies amplitude constraints to solve the input phase.The simulation and experiment prove that the GSW algorithm has better effect on focusing complex targets than the time inversion method.