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

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. (C) 2019 Optical Society of America