691 research outputs found
Coherent control of birefringence and optical activity
Control of polarization of light with light is demonstrated in thin slabs of linear material promising ultrafast all-optical data processing at arbitrarily low intensities. In proof-of-principle experiments we access any polarization azimuth and any ellipticity
Coherent control of Snell's law at metasurfaces
It was recently demonstrated that the well-known Snell's law must be corrected for phase gradient metasurfaces to account for their spatially varying phase, leading to normal and anomalous transmission and reflection of light on such metasurfaces. Here we show that the efficiency of normal and anomalous transmission and reflection of light can be controlled by the intensity or phase of a second coherent wave. The phenomenon is illustrated using gradient metasurfaces based on V-shaped and rectangular apertures in a metal film. This coherent control effect can be exploited for wave front shaping and signal routing
Coherent control of light interaction with graphene
We report the experimental observation of all-optical modulation of light in
a graphene film. The graphene film is scanned across a standing wave formed by
two counter-propagating laser beams in a Sagnac interferometer. Through a
coherent absorption process the on-axis transmission is modulated with close to
80% efficiency. Furthermore we observe modulation of the scattered energy by
mapping the off-axis scattered optical signal: scattering is minimized at a
node of the standing wave pattern and maximized at an antinode. The results
highlight the possibility to switch and modulate any given optical interaction
with deeply sub-wavelength films.Comment: 4 pages, 4 figure
Coherent control of Snell's law
We demonstrate coherent control of the generalized Snell's law in ultrathin gradient metasurfaces constructed by an array of V-shaped slot nanoantennas
Resonant enhancement of second harmonic generation in the mid-infrared using localized surface phonon polaritons in sub-diffractional nanostructures
We report on strong enhancement of mid-infrared second harmonic generation
(SHG) from SiC nanopillars due to the resonant excitation of localized surface
phonon-polaritons within the Reststrahlen band. The magnitude of the SHG peak
at the monopole mode experiences a strong dependence on the resonant frequency
beyond that described by the field localization degree and the dispersion of
linear and nonlinear-optical SiC properties. Comparing the results for the
identical nanostructures made of 4H and 6H SiC polytypes, we demonstrate the
interplay of localized surface phonon polaritons with zone-folded weak phonon
modes of the anisotropic crystal. Tuning the monopole mode in and out of the
region where the zone-folded phonon is excited in 6H-SiC, we observe a
prominent increase of the already monopole-enhanced SHG output when the two
modes are coupled. Envisioning this interplay as one of the showcase features
of mid-infrared nonlinear nanophononics, we discuss its prospects for the
effective engineering of nonlinear-optical materials with desired properties in
the infrared spectral range.Comment: 16 pages, 3 figure
Metamaterials with magnetism and chirality
This review introduces and overviews electromagnetism in structured metamaterials which undergo simultaneous time-reversal and space-inversion symmetry breaking due to magnetism and chirality. Direct experimental observation of optical magnetochiral effects in a single metamolecule with magnetism and chirality is demonstrated at microwave frequencies. Numerical simulations based on a finite element method reproduce the experimental results well, and predict the emergence of giant magnetochiral effects, by combining resonances in the metamolecule. Toward the realization of magnetochiral effects at higher frequencies than microwaves, a metamolecule is miniaturized in the presence of ferromagnetic resonance in a cavity and coplanar waveguide. This work opens the door to the realization of a one-way mirror and synthetic gauge fields for electromagnetic waves
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