Surface plasmon waves carry an intrinsic transverse spin angular momentum, which is locked to their propagation direction. On the other hand, helical plasmonic distributions may also carry an orbital angular momentum that is linked to the field topology. Apparently, when such a singular plasmonic mode propagates on a surface or is guided on a conic structure its helicity and the transverse spin can be coupled to the far-field spin and orbital angular momentum. We discuss the mechaism of such a coupling by using 2D and 3D guiding architetures. We analyze the coupling eﬃciency in each case as well as the intriguing spin-locking phenomenon occurring in our system. Finally we experimentally demonstrate the eﬃcient beaming of a single-handed mode decorated by a desired orbital angular using accurately fabricated nanostructures.
The eﬀect of circularly polarized beaming excited by traveling surface plasmons, via chiral metasurface is experimentally studied. Here we show that the propagation direction of the plasmonic wave, evanescently excited on the thin gold film aﬀects the handedness of the scattered beam polarization. Nanostructured metasurface leads to excitation of localized plasmonic modes whose relative spatial orientation induces overall spin-orbit interaction. This eﬀect is analogical to the rack-and-pinion gear: the rotational motion into the linear motion converter. From the practical point of view, the observed eﬀect can be utilized in integrated optical circuits for communication systems, cyber security and sensing.
We propose a conceptually novel scheme for generation and beaming of optical angular momentum using plasmonic
multilayer nanostructure We calculate the optical modes generated by the structure in near and far-field. Our proposed
structure architecture, consisting of a plasmonic vortex lens is shown to convert impinging light to an almost pure and
well defined orbital angular momentum state capable of propagating to the far-field.
The spin-Hall effect - the influence of the intrinsic spin on the electron trajectory, which produces transverse
deflection of the electrons, is a central tenet in the field of spintronics. Apparently, the handedness of the light's
polarization (optical spin up/down) may provide an additional degree of freedom in nanoscale photonics. The direct
observation of optical spin-Hall effect that appears when a wave carrying spin angular momentum interacts with
plasmonic nanostructures is presented. The measurements verify the unified geometric phase, demonstrated by the
observed spin-dependent deflection of the surface waves as well as spin-dependent enhanced transmission through
coaxial nanoapertures even in rotationally symmetric structures. Moreover, spin-orbit interaction is demonstrated by
use of inhomogeneous and anisotropic subwavelength dielectric structures. The observed effects inspire one to
investigate other spin-based plasmonic effects and to propose a new generation of optical elements for nanophotonic
An extraordinary coherent thermal emission from an anisotropic microstructure is experimentally and theoretically
presented. The enhanced coherency is due to coherent coupling between resonant cavities obtained by surface standing
waves, where each cavity supports a localized field that is attributed to coupled surface phonon-polaritons. We show that
it is possible to obtain a polarized quasi-monochromatic thermal source from a SiC microstructure with a high quality
factor Q ~ 600 at the resonant frequency of the cavity, and a spatial coherence length 760λ which corresponds to angular
divergence of 1.3mrad.
Surface waves have been shown to play a key role in spontaneous thermal emission in the near-field as well as the
coherence and the polarization properties of the nonradiative field. The near-field coherence of the delocalized
nonradiative surface waves can be transferred into radiative fields by introducing a shallow grating on the surface. We
show that the coherency of the thermal radiation can be enhanced by an order of magnitude compared with the
coherency imposed by the delocalized surface waves. The enhanced coherency is due to coherent coupling between
resonant cavities obtained by surface standing waves, where each cavity supports localized field that is attributed to
coupled surface waves. We realized coupled resonant cavity structure on amorphous SiO2 and crystalline SiC, both
support surface phonon-polaritons, to demonstrate extraordinary coherent thermal emission with a high quality factor of
600 and a spatial coherence length of 760λ (8.8mm).
The Pancharatnam-Berry phase is a geometric phase associated with the polarization of light. We present novel optical
phase elements based on the space-domain Pancharatnam-Berry phase. Such elements can be realized using
inhomogeneous anisotropic micro and nanostructures, where the geometric phase is induced by spin-to orbital angular
momentum transfer. The elements are polarization dependent, thereby enabling multipurpose optical elements. Vectorial
vortices, and vectorial vortex mode transformation for a hollow waveguide are demonstrated. Manipulating of thermal
radiation by use of anisotropic micro and nanostructures is also investigated. We demonstrate an extraordinary coherent
thermal radiation from coupled resonant cavities; each of them supports standing wave surface polaritons.
We present a unique method for real-time polarization measurement by use of a discrete space-variant subwavelength grating. The formation of the grating is done by discrete orientation of the local subwavelength grooves. The complete polarization analysis of the incident beam is determined by spatial Fourier transform of the near-field intensity distribution transmitted through the discrete subwavelength dielectric grating followed by a subwavelength metal polarizer. We discuss a theoretical analysis based on Stokes-Muller formalism and experimentally demonstrate our approach with polarization measurements of infrared radiation at a wavelength of 10.6um. Moreover, a new far-field polarimetry approach is presented along with preliminary experimental results.