720,272 research outputs found
From Cavity Electromechanics to Cavity Optomechanics
We present an overview of experimental work to embed high-Q mesoscopic
mechanical oscillators in microwave and optical cavities. Based upon recent
progress, the prospect for a broad field of "cavity quantum mechanics" is very
real. These systems introduce mesoscopic mechanical oscillators as a new
quantum resource and also inherently couple their motion to photons throughout
the electromagnetic spectrum.Comment: 8 pages, 6 figures, ICAP proceedings submissio
Effects of mode degeneracy in the LIGO Livingston Observatory recycling cavity
We analyze the electromagnetic fields in a Pound-Drever-Hall locked,
marginally unstable, Fabry-Perot cavity as a function of small changes in the
cavity length during resonance. More specifically, we compare the results of a
detailed numerical model with the behavior of the recycling cavity of the Laser
Interferometer Gravitational-wave Observatory (LIGO) detector that is located
in Livingston, Louisiana. In the interferometer's normal mode of operation, the
recycling cavity is stabilized by inducing a thermal lens in the cavity mirrors
with an external CO2 laser. During the study described here, this thermal
compensation system was not operating, causing the cavity to be marginally
optically unstable and cavity modes to become degenerate. In contrast to stable
optical cavities, the modal content of the resonating beam in the uncompensated
recycling cavity is significantly altered by very small cavity length changes.
This modifies the error signals used to control the cavity length in such a way
that the zero crossing point is no longer the point of maximum power in the
cavity nor is it the point where the input beam mode in the cavity is
maximized.Comment: Eight pages in two-column format. Six color figures. To be published
JOSA
Observation of dressed intra-cavity dark states
Cavity electromagnetically induced transparency in a coherently prepared
cavity-atom system is manifested as a narrow transmission peak of a weak probe
laser coupled into the cavity mode. We show that with a resonant pump laser
coupling the cavity-confined four-level atoms from free space, the narrow
transmission peak of the cavity EIT is split into two peaks. The two peaks
represent the dressed intra-cavity dark states and have a frequency separation
approximately equal to the Rabi frequency of the free-space pump laser. We
observed experimentally the dressed intra-cavity dark states in cold Rb atoms
confined in a cavity and the experimental results agree with theoretical
calculations based on a semiclassical analysis.Comment: 10 pages, 6 figure
Motion Induced Radiation from a Vibrating Cavity
We study the radiation emitted by a cavity moving in vacuum. We give a
quantitative estimate of the photon production inside the cavity as well as of
the photon flux radiated from the cavity. A resonance enhancement occurs not
only when the cavity length is modulated but also for a global oscillation of
the cavity. For a high finesse cavity the emitted radiation surpasses radiation
from a single mirror by orders of magnitude.Comment: 4 pages, to appear in Physical Review Letter
Cavity enhanced storage - preparing for high efficiency quantum memories
Cavity assisted quantum memory storage has been proposed [PRA 82, 022310
(2010), PRA 82, 022311 (2010)] for creating efficient (close to unity) quantum
memories using weakly absorbing materials. Using this approach we
experimentally demonstrate a significant (about 20-fold) enhancement in quantum
memory efficiency compared to the no cavity case. A strong dispersion
originating from absorption engineering inside the cavity was observed, which
directly affect the cavity line-width. A more than 3 orders of magnitude
reduction of cavity mode spacing and cavity line-width from GHz to MHz was
observed. We are not aware of any previous observation of several orders of
magnitudes cavity mode spacing and cavity line-width reduction due to slow
light effects.Comment: 13 pages, 5 figure
Cavity QED with optically transported atoms
Ultracold Rb atoms are delivered into a high-finesse optical
micro-cavity using a translating optical lattice trap and detected via the
cavity field. The atoms are loaded into an optical lattice from a magneto-optic
trap (MOT) and transported 1.5 cm into the cavity. Our cavity satisfies the
strong-coupling requirements for a single intracavity atom, thus permitting
real-time observation of single atoms transported into the cavity. This
transport scheme enables us to vary the number of intracavity atoms from 1 to
100 corresponding to a maximum atomic cooperativity parameter of 5400, the
highest value ever achieved in an atom--cavity system. When many atoms are
loaded into the cavity, optical bistability is directly measured in real-time
cavity transmission.Comment: 4 figures, 4 page
Cavity basics
The fields in rectangular and circular waveguides are derived from Maxwell's
equations by superposition of plane waves. Subsequently the results are applied
to explain cavity modes. Interaction of the cavity modes with a charged
particle beam leads to the fundamental parameters used to describe the
performance of accelerating cavities. Finally an introduction to multi-gap
cavities is given by the example of travelling-wave structures.Comment: 17 pages, contribution to the CAS - CERN Accelerator School:
Specialised Course on RF for Accelerators; 8 - 17 Jun 2010, Ebeltoft, Denmar
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