Determination of the topological charge of a bessel-gauss beam using the diffraction pattern through of an equilateral aperture

The topological charge TC of an electromagnetic wave is relate with their wavefront spatial distribution. Electromagnetic waves with factor azimuthal exp(ilθ) in its phase, have TC integer (l=m) or non-integer (l=M). These electromagnetic waves with a well-defined of TC can be produced in the visibl...