Study on holographic grating diffraction for Laguerre--Gaussian beam generation

Laguerre--Gaussian beams, as a special model with spiral phasestructure, have been intensively investigated. Holographic gratingmethod is a convenient method of generating Laguerre--Gaussian beamsand measuring their orbital angular momenta. But due to someinevitable adverse factors such as lateral displacement, angulardeflection and elliptical incident profile of incident beam, thepractical effectiveness should be reevaluated. This paper is devotedto the study on the influences of the abovementioned three adversefactors on the holographic grating method. The characteristics ofthe mode decomposition of diffractive order and the relative powersof the orbital angular momentum eigen-states are also given.