Modal description of paraxial structured light propagation: tutorial

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 same time offer an intuitive understanding for why certain classes fields as they do. We concept theoretically, compare it approach, confirm its veracity experimentally using range instructive examples. believe this propagating will be useful addition toolbox optical fields.