2,106 research outputs found
Optomechanical creation of magnetic fields for photons on a lattice
We propose using the optomechanical interaction to create artificial magnetic
fields for photons on a lattice. The ingredients required are an optomechanical
crystal, i.e. a piece of dielectric with the right pattern of holes, and two
laser beams with the right pattern of phases. One of the two proposed schemes
is based on optomechanical modulation of the links between optical modes, while
the other is an lattice extension of optomechanical wavelength-conversion
setups. We illustrate the resulting optical spectrum, photon transport in the
presence of an artificial Lorentz force, edge states, and the photonic
Aharonov-Bohm effect. Moreover, wWe also briefly describe the gauge fields
acting on the synthetic dimension related to the phonon/photon degree of
freedom. These can be generated using a single laser beam impinging on an
optomechanical array
Luther on the Study and Use of the Ancient Languages
Indeed, if the languages were of no practical benefit, we ought still to feel an interest in them as a wonderful gift of God, with which He has now blessed Germany almost beyond all other lands. We do not find many instances in which Satan has fostered them through the universities and cloisters; on the contrary, these institutions have fiercely inveighed, and continue to inveigh, against them
Mechanical oscillation and cooling actuated by the optical gradient force
In this work we combine the large per-photon optical gradient force with the
sensitive feedback of a high quality factor whispering-gallery microcavity. The
cavity geometry, consisting of a pair of silica disks separated by a nanoscale
gap, shows extremely strong dynamical backaction, powerful enough to excite
giant coherent oscillations even under heavily damped conditions (mechanical
Q=4). In vacuum, the threshold for regenerative mechanical oscillation is
lowered to an optical input power of only 270-nanoWatts, or roughly 1000 stored
cavity photons, and efficient cooling of the mechanical motion is obtained with
a temperature compression factor of 13-dB for 4-microWatts of dropped optical
input power.Comment: 29 pages, 8 figure
Multispectral Quantum Dots-in-a-Well Infrared Detectors Using Plasmon Assisted Cavities
We present the design, fabrication, and characterization, of multi-spectral quantum dots-in-a-well (DWELL) infrared detectors, by the integration of a surface plasmon assisted resonant cavity with the infrared detector. A square lattice and rectangular lattice cavity, formed by modifying the square lattice have been used in this design. By confining the resonant mode of the cavity to detector active region, the detector responsivity and detectivity have been improved by a factor of 5. A spectral tuning of 5.5 to 7.2 μm has been observed in the peak response of the detectors, by tuning the lattice constant of the cavity. Simulations indicate the presence of two modes of absorption, which have been experimentally verified. The use of a rectangular lattice predicts highly polarization sensitive modes in x- and y-direction, which are observed in fabricated detectors. A peak detectivity of 3.1 x 10^9 cm √(Hz)/W was measured at 77 K. This design offers a cost-effective and simple method of encoding spectral and polarization information, in infrared focal plane arrays
A multi-spectral and polarization-selective surface-plasmon resonant mid-infrared detector
We demonstrate a multi-spectral polarization sensitive mid-infrared
dots-in-a-well (DWELL) photodetector utilizing surface-plasmonic resonant
elements, with tailorable frequency response and polarization selectivity. The
resonant responsivity of the surface-plasmon detector shows an enhancement of
up to 5 times that of an unpatterned control detector. As the plasmonic
resonator involves only surface patterning of the top metal contact, this
method is independent of light-absorbing material and can easily be integrated
with current focal plane array processing for imaging applications.Comment: 8 pages, 3 figure
Phonon laser action in a tunable, two-level photonic molecule
The phonon analog of an optical laser has long been a subject of interest. We
demonstrate a compound microcavity system, coupled to a radio-frequency
mechanical mode, that operates in close analogy to a two-level laser system. An
inversion produces gain, causing phonon laser action above a pump power
threshold of around 50 W. The device features a continuously tunable, gain
spectrum to selectively amplify mechanical modes from radio frequency to
microwave rates. Viewed as a Brillouin process, the system accesses a regime in
which the phonon plays what has traditionally been the role of the Stokes wave.
For this reason, it should also be possible to controllably switch between
phonon and photon laser regimes. Cooling of the mechanical mode is also
possible.Comment: 4 pages, 4 figure
High temperature cavity polaritons in epitaxial Er_2O_3 on silicon
Cavity polaritons around two Er^(3+) optical transitions are observed in microdisk resonators fabricated from epitaxial Er_2O_3 on Si(111). Using a pump-probe method, spectral anticrossings and linewidth averaging of the polariton modes are measured in the cavity transmission and luminescence at temperatures above 361 K
Nanoscale quantum dot infrared sensors with photonic crystal cavity
We report high performance infrared sensors that are based on intersubband transitions in nanoscale self-assembled quantum dots combined with a microcavity resonator made with a high-index-contrast two-dimensional photonic crystal. The addition of the photonic crystal cavity increases the photocurrent, conversion efficiency, and the signal to noise ratio (represented by the specific detectivity D*) by more than an order of magnitude. The conversion efficiency of the detector at Vb=–2.6 V increased from 7.5% for the control sample to 95% in the PhC detector. In principle, these photonic crystal resonators are technology agnostic and can be directly integrated into the manufacturing of present day infrared sensors using existing lithographic tools in the fabrication facility
Snowflake phononic topological insulator at the nanoscale
We show how the snowflake phononic crystal structure, which recently has been realized experimentally, can be turned into a topological insulator for mechanical waves. This idea, based purely on simple geometrical modifications, could be readily implemented on the nanoscale
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