85 research outputs found
Temporal summation in a neuromimetic micropillar laser
Neuromimetic systems are systems mimicking the functionalities orarchitecture
of biological neurons and may present an alternativepath for efficient
computing and information processing. We demonstratehere experimentally
temporal summation in a neuromimetic micropillarlaser with integrated saturable
absorber. Temporal summation is theproperty of neurons to integrate delayed
input stimuli and to respondby an all-or-none kind of response if the inputs
arrive in a sufficientlysmall time window. Our system alone may act as a fast
optical coincidence detector and paves the way to fast photonic spike
processing networks
Nonlinear mechanics with photonic crystal nanomembranes
Optomechanical systems close to their quantum ground state and nonlinear
nanoelectromechanical systems are two hot topics of current physics research.
As high-reflectivity and low mass are crucial features to improve
optomechanical coupling towards the ground state, we have designed, fabricated
and characterized photonic crystal nanomembranes, at the crossroad of both
topics. Here we demonstrate a number of nonlinear effects with these membranes.
We first characterize the nonlinear behavior of a single mechanical mode and we
demonstrate its nonlocal character by monitoring the subsequent
actuation-related frequency shift of a different mode. We then proceed to study
the underlying nonlinear dynamics, both by monitoring the phase-space
trajectory of the free resonator and by characterizing the mechanical response
in presence of a strong pump excitation. We observe in particular the frequency
evolution during a ring-down oscillation decay, and the emergence of a phase
conjugate mechanical response to a weaker probe actuation. Our results are
crucial to understand the full nonlinear features of the PhC membranes, and
possibly to look for nonlinear signatures of the quantum dynamics
Ultra-low threshold polariton lasing in photonic crystal cavities
The authors show clear experimental evidence of lasing of exciton polaritons
confined in L3 photonic crystal cavities. The samples are based on an InP
membrane in air containing five InAsP quantum wells. Polariton lasing is
observed with thresholds as low as 120 nW, below the Mott transition, while
conventional photon lasing is observed for a pumping power one to three orders
of magnitude higher.Comment: 4 pages, 3 figure
Demonstration of coherent emission from high- photonic crystal nanolasers at room temperature
We report on lasing at room temperature and at telecommunications wavelength
from photonic crystal nanocavities based on InAsP/InP quantum dots. Such laser
cavities with a small modal volume and high quality factor display a high
spontaneous emission coupling factor beta. Lasing is confirmed by measuring the
second order autocorrelation function. A smooth transition from chaotic to
coherent emission is observed, and coherent emission is obtained at 8 times the
threshold power
Floquet control of optomechanical bistability in multimode systems
Cavity optomechanical systems enable fine manipulation of nanomechanical
degrees of freedom with light, adding operational functionality and impacting
their appeal in photonic technologies. We show that distinct mechanical modes
can be exploited with a temporally modulated laser drive to steer between
bistable steady states induced by changes of cavity radiation pressure. We
investigate the influence of thermo-optic nonlinearity on these Floquet
dynamics and find that it can inhibit or enhance the performance of the
coupling mechanism in contrast to their often performance limiting character.
Our results provide new techniques for the characterization of thermal
properties and the control of optomechanical systems in sensing and
computational application
Thermal Excitation of Broadband and Long-range Surface Waves on SiO 2 Submicron Films
We detect thermally excited surfaces waves on a submicron SiO 2 layer,
including Zenneck and guided modes in addition to Surface Phonon Polaritons.
The measurements show the existence of these hybrid thermal-electromagnetic
waves from near-(2.7 m) to far-(11.2 m) infrared. Their propagation
distances reach values on the order of the millimeter, several orders of
magnitude larger than on semi-infinite systems. These two features, spectral
broadness and long range propagation, make these waves good candidates for
near-field applications both in optics and thermics due to their dual nature.Comment: Applied Physics Letters, American Institute of Physics, 201
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