Abstract

Laser beams can possess features which are rather new for traditional optics. For instance, Laguerre-Gaussian $L{G}_p^l$modes with nonzero lindex have azimuth phase dependence and therefore helicoidal wave fronts, with the pitch equal to lλ, where λ is the wavelength [1]. When l= 1, the wavefront shape is a single-started helicoid, and due to the phase singularity on the axis, the amplitude vanish there. For l> 1, the wave front consists from lidentical l-started embedded helicoids, distanced on one wavelength. Now a term Optical Vortex (OV) is widely used for description of such beams, because of the similarity between vortices in nature and in light propagation [2]. This similarity appears, for instance, in the presence of an orbital angular momentum carrying by OV beam [3].

© 2000 IEEE