First the existence of boundary diffracting waves in laser far field was detected. Comparing of experimental results with the published data leads to conclusion that this is the universal phenomena inseparably linked with the diffraction of amplitude non-uniform electromagnetic waves on limiting apertures.
Sergey P. Anokhov,
"Detailed study of plane-plane cavity fundamental mode far-field structure", Proc. SPIE 4018, Optoelectronic Metrology, (13 December 1999); doi: 10.1117/12.373734; https://doi.org/10.1117/12.373734