Formation of radially and azimuthally polarized Bessel light beams under the interaction with a layered - Periodical medium having defect inclusions

A method of transformation of Bessel light beams (BLBs) with an arbitrary cone angle into beams having radially (-) and azimuthally (-) polarization is suggested and elaborated. This method is based on the use of interaction of radiation with a periodical medium having defect inclusion in the form of an anisotropic layer. It is shown that owing to variation of parameters of defect inclusions one can realise a controllable effect on interference maxima of transmission of the periodical medium. Due to the phase difference of orthogonal polarized eigen waves of in passing through every period of the medium, photonic band gaps (PBGs), corresponding to different eigen waves, are splitting and shifting with respect to each other. Such a shift can result in the overlapping of regions of significant reflection of one eigen mode with a region of high transmission of another eigen wave. This enables one to separate and consequently spatially select radially and azimuthally polari zed Bessel light beams. An advantage of the suggested method of formation of - and -polarized BLBs is the possibility of its realization for any wavelength. This is easily attained by tuning the cone angle of the incident circularly polarized BLB.