2,599 research outputs found
Perfect imaging: they don't do it with mirrors
Imaging with a spherical mirror in empty space is compared with the case when
the mirror is filled with the medium of Maxwell's fish eye. Exact
time-dependent solutions of Maxwell's equations show that perfect imaging is
not achievable with an electrical ideal mirror on its own, but with Maxwell's
fish eye in the regime when it implements a curved geometry for full
electromagnetic waves
Switching Exciton Pulses Through Conical Intersections
Exciton pulses transport excitation and entanglement adiabatically through
Rydberg aggregates, assemblies of highly excited light atoms, which are set
into directed motion by resonant dipole-dipole interaction. Here, we
demonstrate the coherent splitting of such pulses as well as the spatial
segregation of electronic excitation and atomic motion. Both mechanisms exploit
local nonadiabatic effects at a conical intersection, turning them from a
decoherence source into an asset. The intersection provides a sensitive knob
controlling the propagation direction and coherence properties of exciton
pulses. The fundamental ideas discussed here have general implications for
excitons on a dynamic network.Comment: Letter with 4 pages and 4 figures. Supplemental material with 4 pages
and 4 figure
Collimating lenses from non-Euclidean transformation optics
Based on the non-Euclidean transformation optics, we design a thin
metamaterial lens that can achieve wide-beam radiation by embedding a simple
source (a point source in three-dimensional case or a line current source in
two-dimensional case). The scheme is performed on a layer-by-layer geometry to
convert curved surfaces in virtual space to flat sheets, which pile up and form
the entire lens in physical space. Compared to previous designs, the lens has
no extreme material parameters. Simulation results confirm its functionality.Comment: 12 pages, 6 figure
An omnidirectional retroreflector based on the transmutation of dielectric singularities
In the field of transformation optics, metamaterials mimic the effect of
coordinate transformations on electromagnetic waves, creating the illusion that
the waves are propagating through a virtual space. Transforming space by
appropriately designed materials makes devices possible that have been deemed
impossible. In particular, transformation optics has led to the demonstration
of invisibility cloaking for microwaves, surface plasmons and infrared light.
Here we report the achievement of another "impossible task". We implement, for
microwaves, a device that would normally require a dielectric singularity, an
infinity in the refractive index. We transmute a singularity in virtual space
into a mere topological defect in a real metamaterial. In particular, we
demonstrate an omnidirectional retroreflector, a device for faithfully
reflecting images and for creating high visibility, from all directions. Our
method is robust, potentially broadband and similar techniques could be applied
for visible light
Perfect imaging with geodesic waveguides
Transformation optics is used to prove that a spherical waveguide filled with
an isotropic material with radial refractive index n=1/r has radial polarized
modes (i.e. the electric field has only radial component) with the same perfect
focusing properties as the Maxwell Fish-Eye lens. The approximate version of
that device using a thin waveguide with a homogenous core paves the way to
experimentally prove perfect imaging in the Maxwell Fish Eye lens
High-dimensional Bell test for a continuous variable state in phase space and its robustness to detection inefficiency
We propose a scheme for testing high-dimensional Bell inequalities in phase
space. High-dimensional Bell inequalities can be recast into the forms of a
phase-space version using quasiprobability functions with the complex-valued
order parameter. We investigate their violations for two-mode squeezed states
while increasing the dimension of measurement outcomes, and finally show the
robustness of high-dimensional tests to detection inefficiency.Comment: 8 pages, 2 figures; title and abstract changed, published versio
Quantum levitation by left-handed metamaterials
Left-handed metamaterials make perfect lenses that image classical
electromagnetic fields with significantly higher resolution than the
diffraction limit. Here we consider the quantum physics of such devices. We
show that the Casimir force of two conducting plates may turn from attraction
to repulsion if a perfect lens is sandwiched between them. For optical
left-handed metamaterials this repulsive force of the quantum vacuum may
levitate ultra-thin mirrors
Ultrahigh sensitivity of slow-light gyroscope
Slow light generated by Electromagnetically Induced Transparency is extremely
susceptible with respect to Doppler detuning. Consequently, slow-light
gyroscopes should have ultrahigh sensitivity
Quantum homodyne tomography with a priori constraints
I present a novel algorithm for reconstructing the Wigner function from
homodyne statistics. The proposed method, based on maximum-likelihood
estimation, is capable of compensating for detection losses in a numerically
stable way.Comment: 4 pages, REVTeX, 2 figure
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