טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentVeksler Dekel
SubjectPhotonic Spin Controlled Multifunctional Metasurfaces
DepartmentDepartment of Nanoscience and Nanotechnology
Supervisor Professor Erez Hasman


Abstract

Photonic metasurfaces are metamaterials with reduced dimensionality composed of engineered sub-wavelength-scale meta-atoms enabling a custom-tailored electromagnetic response of the medium. Geometric phase based on Pancharatnam-Berry phase is a promising approach for achieving an abrupt phase change by space-variant polarization manipulations, leveraging the design of gradient metasurfaces (GMs). During the last years we developed and demonstrated helicity (photon spin) dependent wave-front shaping based on geometric GMs, but it was done for the mid-infrared wavelength and for single beam shaping. Only recently, we extended our approach to the visible spectrum utilizing Si-based geometric GMs. In this thesis we extended the planar optics into multifunctional GMs to achieve multi-mode and multi-tasking geometric GMs. We studied the abilities to control the phase, polarization and amplitude of the light beams. The research was done for beam shaping of incident light in the far field as well as for generation of multiple surface plasmon polariton waves. We investigated a novel generic concept to control photonic transport exploiting the peculiarities of disordered metasurfaces to support multiple wave-fronts in a single GM. Two approaches were implemented. First, GMs based on anisotropic nano-hole nano-antennas for transmission and near field modes operations and second, GMs based on gap plasmon resonator nano-antennas for reflection mode operation. The realization of this research is expected to provide the community with a new platform and new set of tools for developing ultrathin, planar optical elements for sophisticated beam shaping, multiple phase-fronts based on geometric GMs.