ABSTRACT
In this chapter, we present our work on the engineering of
structured light with orbital angular momentum (OAM) using
aperiodic arrays ofmetallic nanoparticles arrangedwith Vogel spiral
geometry. In particular, we introduce and discuss the distinctive
structural properties of different types of Vogel spirals and we
demonstrate the ability to encode specific numerical sequences,
determined by the aperiodic geometry, onto the azimuthal OAM
values of diffracted optical beams. Finally, using Fourier-Hankel
mode decomposition and interferometric reconstruction of the
complex scattered far-fields, we prove experimentally the controlled
generation of large OAM azimuthal values, in excellent agreement
with analytical scattering theory. The engineering of diffracted
beams with controllable OAM spectra using flat aperiodic plasmon
arrays is relevant to a number of applications in singular optics,
classical, and quantum cryptography.
