Experimental Study Of Wavefront Shaping Technology Based On Dopc To Focus Light Through Disordered Media

Multiple scattering occurs when light propagates through a disordered medium.The existence of multiple scattering phenomena severely restricts the application of light in biomedical applications.In order to overcome the influence of light scattering in the disordered medium and realize the focusing and imaging of light through the disordered media wavefront shaping technology has been proposed and developed rapidly in recent years.The current wavefront shaping techniques are divided into three categories:iterative optimization wavefront shaping technology,transmission matrix wavefront shaping technology and optical phase conjugate wavefront shaping technology.The iterative optimization wavefront shaping technique and the transmission matrix wavefront shaping technique have a long focusing time and are difficult to be applied in living biological tissues.The optical phase conjugate wavefront shaping technology can achieve rapid focusing due to its time inversion characteristics,and has broad medical application prospects.Based on the optical phase conjugate principle and the four-step phase shift interference method,this paper combines wavefront shaping technology to achieve the focus of light through the disordered media.In this experiment,a new DOPC optical path system was built,which realized the multiple utilization of SLM,fully utilized the function of SLM,and simplified the experimental optical path.A new SLM and CCD alignment scheme was proposed during the experiment,and good alignment results were obtained,and has the following advantages:First,it is not necessary to make a high-precision physical mask;secondly,it is not necessary to use an SLM capable of amplitude modulation for experiment;most importantly,the alignment method is simple and easy to operate,and takes less time.Moreover,if the optical path disturbance occurs or the alignment is found to be deviated during the experiment,the alignment process can be re-executed at any time,which has better applicability.The alignment scheme in this experiment solved the most critical problem in the DOPC experiment.At the same time,a new method for compensating the reference beam quality and the surface curvature of the SLM is proposed,which improves the enhancement factor of the focusing result.