Here we outline a description of paraxial light propagation from modal perspective. By decomposing the initial transverse field into spatial basis whose elements have known and analytical characteristics, are able to analytically propagate any desired field, making calculation fast easy. selecting other than that planes waves, overcome problem numerical artifacts in angular spectrum approach at...

The propagation of a Laguerre-Gaussian (LG) beam through dispersive medium is investigated. effect the doughnut-like intensity profile probe LG on group velocity studied. We find an analytical expression for out optical axis and compare with its projection onto axis. It turned that vector along at waist Rayleigh range. numerically analytically investigate helical phase front coupling field in f...