Potential of Bessel spiral zone plate in complex beam shaping and structuring

Abstract

We aim here to show that azimuthal structuring of the optical beam may be realized by apodizing a spiral zone plate using an azimuthal-modulated Bessel function. Furthermore, we demonstrate that the azimuthal modulation of a Bessel beam may cause its transmittance to take negative values in azimuth. Accordingly, when a diffractive element (herein, spiral zone plate) is apodized by such a modulated Bessel function, its transmittance undergoes an azimuthal phase change. Consequently, the phase change is imposed on a beam passing through the element. This means that the technique enables us to produce a variety of azimuthal beam shapes, such as spiral, ring-lattice, light-arm, and multi-spot beams. In this research, we illustrate how these structures and shapes are produced and tailored. To verify the consequences of the simulation, corresponding experiments were planned.