50 research outputs found
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
Laser Pulse Heating of Spherical Metal Particles
We consider a general problem of laser pulse heating of spherical metal
particles with the sizes ranging from nanometers to millimeters. We employ the
exact Mie solutions of the diffraction problem and solve heat-transfer
equations to determine the maximum temperature at the particle surface as a
function of optical and thermometric parameters of the problem. The main
attention is paid to the case when the thermometric conductivity of the
particle is much larger than that of the environment, as it is in the case of
metal particles in fluids. We show that in this case at any given finite
duration of the laser pulse the maximum temperature rise as a function of the
particle size reaches an absolute maximum at a certain finite size of the
particle, and we suggest simple approximate analytical expressions for this
dependence which covers the entire range of variations of the problem
parameters and agree well with direct numerical simulations.Comment: 7 pages, 6 figure
Optical generation of intense ultrashort magnetic pulses at the nanoscale
Generating, controlling and sensing strong magnetic fields at ever shorter time and length scales is important for both fundamental solid-state physics and technological applications such as magnetic data recording. Here, we propose a scheme for producing strong ultrashort magnetic pulses localized at the nanoscale. We show that a bimetallic nanoring illuminated by femtosecond laser pulses responds with transient thermoelectric currents of picosecond duration, which in turn induce Tesla-scale magnetic fields in the ring cavity. Our method provides a practical way of generating intense nanoscale magnetic fields with great potential for materials characterization, terahertz radiation generation and data storage applications