Study On Theory And Application Of Laser Speckle Field Phase Singulatities

Laser speckle field is complicated random coherent light field scattered through the random media or on the rough surface. Phase vortex is formed around zero-point of the speckle intensity field with abundant amplitude and phase information, so the researches on the phase vortices are paid great attention and become a hot spot in non-linear optics, laser physics, optical information process, laser display and so on. The singularity-phenomena of field are common in the physics fields of eigenstate of angular momentum, vortex of superfluid, Bose-Einstein condense and crystallography. It also finds wide application in the field of optical micro-control, quantum entanglement and information transmission. Research on the phase singularity properties is not only a new topic in phase vortex of the speckle field, but also has potential applications in the frontier of related optics and physics.In this paper, the most current theories and methods in the frontier of phase singularity phenomena are discussed on the speckle field scattered by Gaussian random surface-scatter. The interaction between laser speckle field and the random surface in motion is researched. The simplified model of speckle in image surface is created. The derivation on the separation of the speckle field's spatio-temporal coherence, caused by the two relative motive random surfaces, is given. Adopting CCD camera as area array detector, the virtual instrument is developed. The extract algorithm and characterization on the speckle phase field are investigated. Based on the theory of random process, the measurement method of speckle statiscal characteristics, area array defector substitute for linear array detector, is presented. The embedded system based on ARM core and Linux is designed. The co-processor of FPGA implements logic processing and video information buffering. The designed experiment proves that the division of the space-time coherent of the speckle field can reduce the speckle effectively. The experiment results are analyzed and discussed. The relation between space-time and singularity is also discussed. In summary, the achievements are acquired as below:1. Propagation and evolution law of singularity in speckle field is analyzed and discussed. The interaction between the coherence light and the random surface is researched based on the scattering theory of Kirchhoff and the mathematical model of simulation are made for investigation on phase singularity theory. The simplified model of optical system adopted in laser display is created.2. The effect of the separation of the speckle field's spatio-temporal coherence caused by two relative motive random surfaces is derived. We adopted the method of analyzing phase singularity field and phase gradient field, which shows the light direction and the of flow energy.3. The declines dimension algorithm is proposed for the statistic characteristics of speckle field. The dynamic speckle contrast is used to characterize the intensity of speckle effect, and the quantity of phase vortices in unit length is used to characterize the speckle statistic size.4. The interference field is acquired by adopting the interference method and the phase field is calculated to analyze the modulation of random surface in motion.The interaction between the coherence light and the random surface was investigated in the subject and the evolution of phase singularity was analyzed. It has an important significance in the research on the phase vortex of the scattering field. The research is especially important to improve the research in phase vortex. The research is significant in the measurement, characteristic of speckle field and speckle removal in laser display.