Bessel and Airy transformation-optics lenses

Contacts:

Andrey Novitsky (DTU Fotonik) anov@fotonik.dtu.dk

The project deals with advanced electromagnetic theory and has important applications in the fields of wave propagation and laser beams. Several years ago the transformation optics concept was formulated. Transformation optics can be applied to achieve the required electromagnetic field distributions in some spatial region, for example complete absence of the fields or in opposite their concentration. Transformation optics allows us to get the material parameters and fields of the complex medium equivalent to the very simple original one. Transition from the simple to complex medium is possible owing to the invariance of the Maxwell equations with respect to a coordinate transformation. In general, the complex medium should be non-uniform, anisotropic, and magnetic, i.e. should be characterized by the tensors of dielectric permittivity and magnetic permeability. Such transformation medium is realized using metamaterials.

A plane slab of a metamaterial converting initial (plane) wave into a spatial field distribution can be called the transformation-optics lens. An example of the transformation lens, which converts an impinging plane wave into the Gaussian beam is illustrated in the figure. This research project is devoted to the determination material tensors of the lenses that convert an initial plane wave into the fields with Bessel and Airy field distributions. Such distributions are called Bessel and Airy electromagnetic beams. It is new and very popular direction of research, because such beams can propagate in non-diffracting regime. The project will require execution both closed-form calculations and numerical simulations using COMSOL Multiphysics.