The evolution of a complex beam width parameter g describing focusing or defocusing of a paraxial Gaussian beam is considered as the cause of an additional topological (Berry) phase of the electromagnetic field associated with the beam. It is pointed out that the well-known Gouy phase is a special case of such a phase that should arise in general in all symplectic systems.
© 1995 Optical Society of America
Original Manuscript: July 28, 1995
Published: November 1, 1995
D. Subbarao, "Topological phase in Gaussian beam optics," Opt. Lett. 20, 2162-2164 (1995)