247 research outputs found
Second-harmonic generation in subwavelength graphene waveguides
We suggest a novel approach for generating second-harmonic radiation in
subwavelength graphene waveguides. We demonstrate that quadratic phase matching
between the plasmonic guided modes of different symmetries can be achieved in a
planar double-layer geometry when conductivity of one of the layers becomes
spatially modulated. We predict theoretically that, owing to graphene nonlocal
conductivity, the second-order nonlinear processes can be actualized for
interacting plasmonic modes with an effective grating coupler to allow external
pumping of the structure and output of the radiation at the double frequency.Comment: 5 pages, 3 figure
Quantum spin Hall effect of light
Maxwell's equations, formulated 150 years ago, ultimately describe properties
of light, from classical electromagnetism to quantum and relativistic aspects.
The latter ones result in remarkable geometric and topological phenomena
related to the spin-1 massless nature of photons. By analyzing fundamental spin
properties of Maxwell waves, we show that free-space light exhibits an
intrinsic quantum spin Hall effect, i.e., surface modes with strong
spin-momentum locking. These modes are evanescent waves that form, e.g.,
surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate
the unusual transverse spin in evanescent waves and explain recent experiments
demonstrating the transverse spin-direction locking in the excitation of
surface optical modes. This deepens our understanding of Maxwell's theory,
reveals analogies with topological insulators for electrons, and offers
applications for robust spin-directional optical interfaces.Comment: 8 pages, 4 figures, Supplementary Material
Optical anapoles in nanophotonics and meta-optics
Interference of electromagnetic modes supported by subwavelength photonic
structures is one of the key concepts that underpins the subwavelength control
of light in meta-optics. It drives the whole realm of all-dielectric
Mie-resonant nanophotonics with many applications for low-loss nanoscale
optical antennas, metasurfaces, and metadevices. Specifically, interference of
the electric and toroidal dipole moments results in a very peculiar,
low-radiating optical state associated with the concept of optical anapole.
Here, we uncover the physics of multimode interferences and multipolar
interplay in nanostructures with an intriguing example of the optical anapole.
We review the recently emerged field of anapole electrodynamics explicating its
relevance to multipolar nanophotonics, including direct experimental
observations, manifestations in nonlinear optics, and rapidly expanding
applications in nanoantennas, active photonics, and metamaterials.Comment: 14 pages, 6 figure
Photonic quantum Hall effects
This article reviews the development of photonic analogues of quantum Hall
effects, which have given rise to broad interest in topological phenomena in
photonic systems over the past decade. We cover early investigations of
geometric phases, analogies between electronic systems and the spectra of
periodic photonic media including photonic crystals, efforts to generalize
topological band theory to open, dissipative, and nonlinear wave systems,
pursuit of useful device applications, and ongoing studies of photonic Hall
effects in classical nonlinear optics and the quantum regime of strong
photon-photon interactions.Comment: Book chapter for Elsevier Encyclopedia of Condensed Matter Physics.
Comments are welcom
Ring Dirac solitons in nonlinear topological systems
We study solitons of the two-dimensional nonlinear Dirac equation with asymmetric cubic nonlinearity. We show that with the nonlinearity parameters specifically tuned, a high degree of localization of both spinor components is enabled on a ring of certain radius. Such ring Dirac soliton can be viewed as a self-induced nonlinear domain wall and can be implemented in nonlinear photonic graphene lattice with Kerr-like nonlinearities. Our model could be instructive for understanding localization mechanisms in nonlinear topological systems.A.N.P. acknowledges the
support of the Australian Research Council and of the “Basis” Foundation. D.A.S. acknowledges the support of the Russian
Foundation for Basic Research (Grant No. 18-02-00381)
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