Vortex light mode detection method based on three-step phase shift method

Abstract

The invention relates to a vortex light mode detection method based on a three-step phase shift method. Vortex light is a special light field with a spiral wave front, and the three-step phase shift method is a phase measurement method. The method comprises the steps of firstly, preparing a hologram of target vortex light; superposing three beams of one-dimensional gratings with phase shifts of 0,0.5 pi and pi on the basis to obtain three new holograms; sequentially recording the intensity distribution of the initial vortex light and the interference distribution of the three beams of phase shift vortex light on the same plane through a spatial light modulator method, and obtaining the complex amplitude distribution of the vortex light in combination with a phase formula; and secondly, carrying out convolution operation on the complex amplitude distribution and standard vortex light bases with different topological charges through a computer to acquire the mode degree and the mode purity of the target vortex light and achieve mode analysis of the target vortex light. The method provided by the invention is simple in optical path and high in flexibility, belongs to the field of vortex light detection, and can be applied to mode detection of complex vortex light.

Description

technical field [0001] The invention relates to a vortex light mode detection method based on a three-step phase shift method. The vortex light is a special light field with a helical wave front. The three-step phase shift method is a phase measurement method. Through the three-step phase shift The complex amplitude distribution of the vortex light can be measured by the method, combined with the mode analysis, the mode degree and mode purity of the target vortex light can be obtained. The method has simple optical path and strong flexibility, belongs to the field of vortex light detection, and can be applied to the pattern detection of complex vortex light. [0002] technical background [0003] Vortex light is a light field with helical wavefront and special light intensity distribution, and Laguerre-Gaussian light is a typical vortex light. In recent years, vortex light has attracted much attention due to its wide application value in optical manipulation, optical communi...

AI Technical Summary

Problems solved by technology

[0008] The technical solution of the present invention is as follows: Aiming at the difficulty and singleness of the current vortex light mode detection method, a vortex light mode analysis method based on the three-step phase shift method is proposed. This method has a simple optical path and strong flexibility. Record three different target vortex beam interference patterns and an intensity distribution map at the same position on a specific plane, then the complex amplitude distribution and topological charge of the target vortex beam at this position can be obtained, and the complex amplitude distribution can be obtained by computer The mode degree and mode purity of the target vortex light can be obtained by convolution operation with the standard vortex light base of different topological charges, so as to realize the mode analysis of the target vortex light

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