ORBITAL ANGULAR MOMENTUM DENSITY OF AN ELEGANT LAGUERRE-GAUSSIAN BEAM

Based on the method of the vectorial angular spectrum, an analytical expression of the electric fleld of an elegant Laguerre- Gaussian beam in free space is derived beyond the paraxial approximation, and the corresponding magnetic fleld is obtained by taking the curl of the electric fleld. By using the expressions for the electromagnetic flelds, the expression of the orbital angular momentum density of the elegant Laguerre-Gaussian beam is derived, which is applicable to both the near and far flelds. The efiects of the three beam parameters on the distribution of the orbital angular momentum density of the elegant Laguerre-Gaussian beam are studied. The distribution of the orbital angular momentum density of the elegant Laguerre-Gaussian beam is also compared with that of the standard Laguerre-Gaussian beam. The result shows that the distribution of the orbital angular momentum density of the elegant Laguerre-Gaussian beam is more simple and centralized than that of the standard Laguerre-Gaussian beam.