Complex beam shaping by cascaded conical diffraction with intercalated polarization transforming elements

Abstract

Cascaded conical diffraction where optical elements modifying the local polarization state are intercalated between the aligned biaxial crystals is analyzed theoretically in the framework of paraxial diffraction theory. The obtained expressions are verified and confirmed experimentally for the case of a two-crystal cascade intercalated by a polarizer or a wave plate. The present approach can be used to realize a variety of vector beams with complex beam shapes composed of concentric rings with strongly modulated azimuthal intensity distribution. A potentially very fast switching of the overall beam shape is possible if the intercalated elements are electro-optically tunable retarders.

Some aspects of scaling the orbital angular momentum of light with conical diffraction

“…This was shown experimentally and theoretically in Ref. [14] with a /4 or a /2 plate or a linear polarizer inserted between two crystals (calculations were also performed with more than two crystals). When polarizers were used, among numerous modes, modes with 1 and 2 ħ/photon OAM (LG 0 1 , LG 1 1 and LG 0 2 Laguerre-Gauss) were exhibited in Ref.…”

Evolution of vortices created by conical diffraction in biaxial crystals versus orbital angular momentum

“…This was shown experimentally and theoretically in Ref. [9] with a /4 or a /2 plate or a linear polarizer inserted between two or more crystals. With the help of polarizers, LG 0 1 ,…”

Dynamic freeform diffractive lens

“…However, since laser beams are described by complex mathematical expressions, full control over them can only be achieved if we are able to change their intensity and wavefront (phase) at will, simultaneously. This shaping procedure is known as complex beam shaping (CBS) [10][11][12][13][14].…”