84 research outputs found
Quantum dot-cavity strong-coupling regime measured through coherent reflection spectroscopy in a very high-Q micropillar
We report on the coherent reflection spectroscopy of a high-quality factor
micropillar, in the strong coupling regime with a single InGaAs annealed
quantum dot. The absolute reflectivity measurement is used to study the
characteristics of our device at low and high excitation power. The strong
coupling is obtained with a g=16 \mueV coupling strength in a 7.3\mum diameter
micropillar, with a cavity spectral width kappa=20.5 \mueV (Q=65 000). The
factor of merit of the strong-coupling regime, 4g/kappa=3, is the current
state-of-the-art for a quantum dot-micropillar system
Exciton photon strong-coupling regime for a single quantum dot in a microcavity
We report on the observation of the strong coupling regime between a single
GaAs quantum dot and a microdisk optical mode. Photoluminescence is performed
at various temperatures to tune the quantum dot exciton with respect to the
optical mode. At resonance, we observe an anticrossing, signature of the strong
coupling regime with a well resolved doublet. The Vacuum Rabi splitting amounts
to 400 μeV and is twice as large as the individual linewidths.Comment: submitted on November 7th 200
Accurate measurement of a 96% input coupling into a cavity using polarization tomography
Pillar microcavities are excellent light-matter interfaces providing an
electromagnetic confinement in small mode volumes with high quality factors.
They also allow the efficient injection and extraction of photons, into and
from the cavity, with potentially near-unity input and output-coupling
efficiencies. Optimizing the input and output coupling is essential, in
particular, in the development of solid-state quantum networks where artificial
atoms are manipulated with single incoming photons. Here we propose a technique
to accurately measure input and output coupling efficiencies using polarization
tomography of the light reflected by the cavity. We use the residual
birefringence of pillar microcavities to distinguish the light coupled to the
cavity from the uncoupled light: the former participates to rotating the
polarization of the reflected beam, while the latter decreases the polarization
purity. Applying this technique to a micropillar cavity, we measure a output coupling and a input coupling with unprecedented
precision.Comment: 6 pages, 3 figure
High frequency GaAs nano-optomechanical disk resonator
Optomechanical coupling between a mechanical oscillator and light trapped in
a cavity increases when the coupling takes place in a reduced volume. Here we
demonstrate a GaAs semiconductor optomechanical disk system where both optical
and mechanical energy can be confined in a sub-micron scale interaction volume.
We observe giant optomechanical coupling rate up to 100 GHz/nm involving
picogram mass mechanical modes with frequency between 100 MHz and 1 GHz. The
mechanical modes are singled-out measuring their dispersion as a function of
disk geometry. Their Brownian motion is optically resolved with a sensitivity
of 10^(-17)m/sqrt(Hz) at room temperature and pressure, approaching the quantum
limit imprecision.Comment: 7 pages, 3 figure
Polariton laser using single micropillar GaAs-GaAlAs semiconductor cavities
Polariton lasing is demonstrated on the zero dimensional states of single
GaAs/GaAlAs micropillar cavities. Under non resonant excitation, the measured
polariton ground state occupancy is found to be as large as . Changing
the spatial excitation conditions, competition between several polariton lasing
modes is observed, ruling out Bose-Einstein condensation. When the polariton
state occupancy increases, the emission blueshift is the signature of
self-interaction within the half-light half-matter polariton lasing mode.Comment: 5 pages, 4 figures, accepted for publication in Physical Review
Letter
Frequency cavity pulling induced by a single semiconductor quantum dot
We investigate the emission properties of a single semiconductor quantum dot
deterministically coupled to a confined optical mode in the weak coupling
regime. A strong pulling, broadening and narrowing of the cavity mode emission
is evidenced when changing the spectral detuning between the emitter and the
cavity. These features are theoretically accounted for by considering the
phonon assisted emission of the quantum dot transition. These observations
highlight a new situation for cavity quantum electrodynamics involving
spectrally broad emitters
Backscattering suppression in supersonic 1D polariton condensates
We investigate the effects of disorder on the propagation of one-dimensional
polariton condensates in semiconductor microcavities. We observe a strong
suppression of the backscattering produced by the imperfections of the
structure when increasing the condensate density. This suppression occurs in
the supersonic regime and is simultaneous to the onset of parametric
instabilities which enable the "hopping" of the condensate through the
disorder. Our results evidence a new mechanism for the frictionless flow of
polaritons at high speeds.Comment: 5 pages, 3 figure
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