Research On Measurement Of Surface Topography Based On Vortex Light And Phase Shifting Interferometry

Vortex light is a special light field with a helical phase wavefront and a central phase singularity.Due to the particularity of its phase,the light intensity of the vortex light is distributed in a circular ring with a dark core in the center.With the rapid development of vortex light in the fields of free optical communication,communication coding,optical capture,optical manipulation,etc.,the research of using vortex light's phase characteristics to carry out precision measurement is also increasing.As high-precision components are widely used in the machine manufacturing industry,the technical demand for high-precision measurement of the surface shape of objects is also increasing.Based on the unique phase properties of vortex light,the method of combining vortex light and phase shift interference measurement has application prospects in the field of high-precision surface topography measurement.In this paper,after the study of various characteristics of vortex light,based on the vortex light phase shift interference technology,the surface shape measurement of the object is studied.This thesis designed an experimental scheme for measuring the surface topography of vortex light as reference light and plane wave as measurement light based on the theory of interference between vortex light and plane wave.In this scheme,a reflective pure phase liquid crystal spatial light modulator is used to generate vortex light,and the digital control of the vortex light is realized by loading images on the liquid crystal spatial light modulator.By capturing the interference image of vortex light and plane wave,combining the principle of phase shift interference and unwrapping algorithm,the surface topography information of the measured object is obtained.In this thesis,the optical software VirtualLab Fusion is used to simulate and analyze the design plan.The vortex light and surface topography are generatedby the liquid crystal spatial light modulator.The comparison of the simulation results and the preset topography verifies the design plan feasibility.Finally,an experimental measurement was made on the surface morphology of the sample using the designed scheme,and an error analysis was given in combination with the experimental results.The study of applying vortex light to the measurement of the surface morphology of objects was realized.