24 research outputs found
Dynamical Coupling between a Bose-Einstein Condensate and a Cavity Optical Lattice
A Bose-Einstein condensate is dispersively coupled to a single mode of an
ultra-high finesse optical cavity. The system is governed by strong
interactions between the atomic motion and the light field even at the level of
single quanta. While coherently pumping the cavity mode the condensate is
subject to the cavity optical lattice potential whose depth depends nonlinearly
on the atomic density distribution. We observe bistability already below the
single photon level and strong back-action dynamics which tunes the system
periodically out of resonance.Comment: 5 pages, 4 figure
Equivalence between free quantum particles and those in harmonic potentials and its application to instantaneous changes
This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedIn quantum physics the free particle and the harmonically trapped particle are arguably the most important systems a physicist needs to know about. It is little known that, mathematically, they are one and the same. This knowledge helps us to understand either from the viewpoint of the other. Here we show that all general time-dependent solutions of the free-particle Schrodinger equation can be mapped to solutions of the Schrodinger equation for harmonic potentials, both the trapping oscillator and the inverted `oscillator'. This map is fully invertible and therefore induces an isomorphism between both types of system, they are equivalent. A composition of the map and its inverse allows us to map from one harmonic oscillator to another with a different spring constant and different center position. The map is independent of the state of the system, consisting only of a coordinate transformation and multiplication by a form factor, and can be chosen such that the state is identical in both systems at one point in time. This transition point in time can be chosen freely, the wave function of the particle evolving in time in one system before the transition point can therefore be linked up smoothly with the wave function for the other system and its future evolution after the transition point. Such a cut-and-paste procedure allows us to describe the instantaneous changes of the environment a particle finds itself in. Transitions from free to trapped systems, between harmonic traps of different spring constants or center positions, or, from harmonic binding to repulsive harmonic potentials are straightforwardly modelled. This includes some time dependent harmonic potentials. The mappings introduced here are computationally more efficient than either state-projection or harmonic oscillator propagator techniques conventionally employed when describing instantaneous (non-adiabatic) changes of a quantum particle's environmentPeer reviewe
Opto-mechanical measurement of micro-trap via nonlinear cavity enhanced Raman scattering spectrum
High-gain resonant nonlinear Raman scattering on trapped cold atoms within a
high-fineness ring optical cavity is simply explained under a nonlinear
opto-mechanical mechanism, and a proposal using it to detect frequency of
micro-trap on atom chip is presented. The enhancement of scattering spectrum is
due to a coherent Raman conversion between two different cavity modes mediated
by collective vibrations of atoms through nonlinear opto-mechanical couplings.
The physical conditions of this technique are roughly estimated on Rubidium
atoms, and a simple quantum analysis as well as a multi-body semiclassical
simulation on this nonlinear Raman process is conducted.Comment: 7 pages, 2 figure
All-optical switching and strong coupling using tunable whispering-gallery-mode microresonators
We review our recent work on tunable, ultrahigh quality factor
whispering-gallery-mode bottle microresonators and highlight their applications
in nonlinear optics and in quantum optics experiments. Our resonators combine
ultra-high quality factors of up to Q = 3.6 \times 10^8, a small mode volume,
and near-lossless fiber coupling, with a simple and customizable mode structure
enabling full tunability. We study, theoretically and experimentally, nonlinear
all-optical switching via the Kerr effect when the resonator is operated in an
add-drop configuration. This allows us to optically route a single-wavelength
cw optical signal between two fiber ports with high efficiency. Finally, we
report on progress towards strong coupling of single rubidium atoms to an
ultra-high Q mode of an actively stabilized bottle microresonator.Comment: 20 pages, 24 figures. Accepted for publication in Applied Physics B.
Changes according to referee suggestions: minor corrections to some figures
and captions, clarification of some points in the text, added references,
added new paragraph with results on atom-resonator interactio
Photonic molecules and spectral engineering
This chapter reviews the fundamental optical properties and applications of
pho-tonic molecules (PMs) - photonic structures formed by electromagnetic
coupling of two or more optical microcavities (photonic atoms). Controllable
interaction between light and matter in photonic atoms can be further modified
and en-hanced by the manipulation of their mutual coupling. Mechanical and
optical tunability of PMs not only adds new functionalities to
microcavity-based optical components but also paves the way for their use as
testbeds for the exploration of novel physical regimes in atomic physics and
quantum optics. Theoretical studies carried on for over a decade yielded novel
PM designs that make possible lowering thresholds of semiconductor microlasers,
producing directional light emission, achieving optically-induced transparency,
and enhancing sensitivity of microcavity-based bio-, stress- and
rotation-sensors. Recent advances in material science and nano-fabrication
techniques make possible the realization of optimally-tuned PMs for cavity
quantum electrodynamic experiments, classical and quantum information
processing, and sensing.Comment: A review book chapter: 29 pages, 19 figure
Microresonator Dissipative Kerr Solitons Synchronized to an Optoelectronic Oscillator
Using phase-modulation-induced potential gradient whose period is synchronized to a microwave optoelectronic oscillator, dissipative Kerr solitons generated in a crystalline optical microresonator are trapped by the soliton tweezing effect, exhibiting a stabilized soliton repetition rate. In the meantime, side-mode suppression of the microwave signal is enabled by the photodetection of the soliton train. Substantiated both experimentally and theoretically, the hybrid system produces a drift-reduced microcomb and a spectrum-purified optoelectronic oscillator simultaneously, yielding a low-cost toolkit for microwave and optical metrology.Wenle Weng, Jijun He, Aleksandra Kaszubowska-Anandarajah, Prince M. Anandarajah, and Tobias J. Kippenber