 Gouy phase of Bessel-Gaussian beams: theory vs. experiment by Lyubomir Stoyanov and others

Optics Express31(9),13683–13699 (2023). Author-hosted primary PDF: quantum.phys.uni-sofia.bg/dreischuh/A89.pdf . Indexed Figure3 caption, p.13691: Mach-Zehnder setup,532nm laser, beam expansion, two spatial light modulators, focusing lenses and rail-mounted CCD. The source studies structured Bessel-Gaussian beams; the original four-step Gaussian example here is a separate illustrative protocol.