A method for determining the direction of a partially-coherent laguerre-gaussian light beam vortex

Abstract

The invention discloses a method for determining the direction of a partially-coherent laguerre-gaussian light beam vortex. A partially-coherent laguerre-gaussian light beam which is to be measured is divided into reference light and pilot light through a spectroscope. The pilot light passes through two cylindrical surface lenses which are perpendicular to each other, and transmits for a distance z, and then asymmetric spatial distribution of pilot light intersecting spectral concentration of the pilot light is measured through an association system; the reference light goes through a light beam analysis system so as to measure light intensity spatial distribution of the light beam; the asymmetric spatial distribution of pilot light intersecting spectral concentration which is measured above and the light intensity spatial distribution of the reference light are subjected to computer processing according to first-order coherence degree vortex distribution characteristics of the laguerre-gaussian light beam to obtain a first-order coherence degree distribution map of the to-be-measured light beam. The deflection direction of a symmetric axis of the distribution map is corresponding to the direction of the partially-coherent laguerre-gaussian light beam vortex. The method provided by the invention for measuring the direction of the light beam coherent vortex does not require expensive apparatuses. The measurement apparatus is simple. The determination is visual. The result is reliable.

Description

technical field [0001] The patent of the present invention provides a method for judging the vortex direction of a partially coherent Laguerre-Gaussian beam. The method can be applied to a partially coherent vortex optical system with low coherence, and belongs to the field of partially coherent optical measurement. Background technique [0002] Optical vortices appear as singular points in light fields. At this position, the amplitude of the light field is zero and the phase cannot be defined. Near the singular point of the light field, the isophase surface presents a spiral distribution. This helical phase distribution makes the optical vortex-carrying optical vortex beams have orbital angular momentum, and thus shows great application prospects in many nearby fields such as optical trapping, atomic manipulation, information storage, and quantum communication. The research on optical vortex develops rapidly and becomes an important branch of modern optics. [0003] In ...

AI Technical Summary

Problems solved by technology

The literature (Effect of spatial coherence on determining the topological charge of avortex beam, APPLIEDPHYSICSLETTERS101, 261104 (2012)) proposed a method to measure the topological charge of a partially coherent vortex beam, but this method can only obtain the size of the vortex but not the direction of the vortex

At present, the method and device for experimentally measuring the vortex direction of partially coherent Laguerre-Gaussian beams are still in a blank state

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