In this paper, we characterize the helical beam structure through an analysis of the spiral character of the phase distribution inside a light beam. In particular, we show that a line connected with the 2π phase jump in the Laguerre–Gauss beam can be described by a Fermat’s spiral. We propose a numerical fitting method to determine the parameters of a spiral equation for the phase distribution of the helical beam. Next, we extend the procedure to a vortex beam created by the spiral phase plate and apply it to experimental phase maps, which allows us to recover the phase shift introduced into the object beam in the optical vortex scanning microscope.

The regular net of optical vortices can be generated by three plane wave interference. Such regular vortices are used in a new kind of interferometry—optical vortex interferometry. In this work, the experimental method for topological charge determination of optical vortices in a regular net is presented. This allows for unique phase reconstruction in optical vortex interferometry and solves what is known in interferometry as the phase unwrapping problem. © 2005 Society of Photo-Optical Instrumentation Engineers.

We propose the use of high-order optical vortices as markers in the positioning of a laser beam. The broken optical vortices are arranged in constellations. The center of gravity of these constellations makes it possible to position the beam carrying information encoded in the optical vortices. This paper describes three positioning methods using both intensity and phase maps. The methods described were tested in experiments performed in a laboratory and an open space.

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