Method for expanding detection range of vortex light OAM state sorter

The invention relates to the technical field of composite vortex light orbital angular momentum separation and detection and light wavefront modulation, and discloses a method for expanding the detection range of a vortex light orbital angular momentum state OAM coordinate transformation sorter, which adds addition and subtraction phases on the basis of the original coordinate transformation sorter. Firstly, to-be-measured light is divided into multiple beams, the multiple beams are respectively incident to addition and subtraction phases with different modulation values, and at the moment, the OAM state of the to-be-measured light of each branch is modulated. And the modulated light beam enters a coordinate transformation sorter to realize OAM state detection, light spot distribution is finally presented on each shunt receiving surface, light spots at different positions correspond to different OAM states, and the OAM state of the original to-be-detected light can be judged by identifying the imaging light s