A5053156697- Cold Atom Physics and Bose-Einstein Condensates
- Quantum optics and atomic interactions
- Atomic and Subatomic Physics Research
- Mechanical and Optical Resonators
- Quantum Information and Cryptography
- Quantum, superfluid, helium dynamics
- Advanced Frequency and Time Standards
- Advanced Fiber Laser Technologies
- Photonic and Optical Devices
- Solar and Space Plasma Dynamics
- Magnetic confinement fusion research
- Physics of Superconductivity and Magnetism
- Spectroscopy and Laser Applications
- Quantum chaos and dynamical systems
- Molecular Junctions and Nanostructures
- Random lasers and scattering media
- Orbital Angular Momentum in Optics
- Dark Matter and Cosmic Phenomena
- Atmospheric Ozone and Climate
- Quantum and electron transport phenomena
- Geomagnetism and Paleomagnetism Studies
- Optical properties and cooling technologies in crystalline materials
- Advanced Measurement and Metrology Techniques
- Scientific Measurement and Uncertainty Evaluation
- Strong Light-Matter Interactions
University of Birmingham
2012-2022
Joint Institute for Laboratory Astrophysics
2014
University of Colorado Boulder
2002-2014
Imperial College London
2007-2011
National Institute of Standards and Technology
2004-2005
Abstract We propose in this White Paper a concept for space experiment using cold atoms to search ultra-light dark matter, and detect gravitational waves the frequency range between most sensitive ranges of LISA terrestrial LIGO/Virgo/KAGRA/INDIGO experiments. This interdisciplinary experiment, called Atomic Experiment Dark Matter Gravity Exploration (AEDGE), will also complement other planned searches exploit synergies with wave detectors. give examples extended sensitivity matter offered...
Three magnetic-field induced heteronuclear Feshbach resonances were identified in collisions between bosonic 87Rb and fermionic 40K atoms their absolute ground states. Strong inelastic loss from an optically trapped mixture was observed at the resonance positions of 492, 512, 543+/-2 G. The locations these place a tight constraint on triplet singlet cross-species scattering lengths, yielding (-281+/-15)a(0) (-54+/-12)a(0), respectively. width feature 543 G is 3.7+/-1.5 wide; this broad...
Abstract We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning status of cold atom technologies, prospective scientific and societal opportunities offered by their deployment space, developments needed before atoms could be operated space. The technologies discussed include atomic clocks, quantum gravimeters accelerometers, interferometers. Prospective applications metrology, geodesy measurement terrestrial mass change due to, e.g., climate change,...
A microfabricated Fabry-Perot optical resonator has been used for atom detection and photon production with less than 1 on average in the cavity mode. Our design combines intrinsic scalability of microfabrication processes direct coupling field to single-mode waveguides or fibers. The presence is seen through changes both intensity noise characteristics probe light reflected from input mirror. An excitation laser passing transversely triggers emission into mode hence fiber. These are first...
Abstract The detection of variations fundamental constants the Standard Model would provide us with compelling evidence new physics, and could lift veil on nature dark matter energy. In this work, we discuss how a network atomic molecular clocks can be used to look for such unprecedented sensitivity over wide range time scales. This is precisely goal recently launched QSNET project: A measuring stability constants. will include state-of-the-art clocks, but also develop next-generation highly...
A quantum degenerate, dilute gas mixture of bosonic and fermionic atoms was produced using $^{87}\mathrm{Rb}$ $^{40}\mathrm{K}$. The onset degeneracy confirmed by observing the spatial distribution gases after time-of-flight expansion. Furthermore, magnitude interspecies scattering length between doubly spin-polarized states $^{40}\mathrm{K}$, $\ensuremath{\mid}{a}_{\mathrm{RbK}}\ensuremath{\mid}$, determined from cross-dimensional thermal relaxation. uncertainty in this collision...
We trap and cool a gas composed of 40K 87Rb, using two-species magneto-optical (MOT). This represents the first step towards cooling Bose-Fermi mixture to quantum degeneracy. Laser light for MOT is derived from laser diodes amplified with single high power semiconductor amplifier chip. The four-color system described, single-species MOTs are characterized. Atom numbers 1x10^7 2x10^9 87Rb trapped in MOT. Observation loss due collisions between species presented future prospects experiment discussed.
Abstract It is usually considered that the spectrum of an optical cavity coupled to atomic medium does not exhibit a normal-mode splitting unless system satisfies strong coupling condition, meaning Rabi frequency coherent exceeds decay rates atom and excitations. Here we show this need be case, but depends on way in which probed. Measurements reflection probe laser from input mirror overdamped reveal avoided crossing observed when driving atoms directly measuring Purcell-enhanced emission....
The avalanche mechanism has been used to relate Efimov trimer states certain enhanced atom loss features observed in ultracold-atom-gas experiments. These are argued be a signature of resonant atom-molecule scattering that occurs when an is degenerate with the threshold. However, observation these yet combined direct for any particular atomic species. In addition, recent Monte Carlo simulations were unable reproduce narrow feature. We experimentally search near established resonance between...
We study modulation-free methods for producing sub-Doppler, dispersive line shapes laser stabilization near the potassium D2 transitions at 767 nm. Polarization spectroscopy is performed and a comparison made between use of mirror or beam splitter aligning counter-propagating pump probe beams. Conventional magnetically-induced dichroism found to suffer from small dispersion large background offset. therefore introduce modified scheme, using two spatially separated pump-probe pairs. Finally...
We demonstrate lasing into counterpropagating modes of a ring cavity using gas cold atoms as gain medium. The laser operates under the usual conditions magneto-optical trapping with no additional fields. characterize threshold behavior and measure second-order optical coherence. emission exhibits directional bistability, switching randomly between clockwise counterclockwise modes, tunable nonreciprocity is observed are displaced along axis.
Electromagnetically induced transparency in a vapor of Rydberg atoms can be used for radio frequency (RF) electric field sensing. Such sensors traceable, tunable, compact, and electrically passive. One application these is as receiver RF communications, converting 5G transmission free space to modulated optical signal fixed network. Different figures merit are an electric-field sensor receiver; so it not straightforward determine under which operating conditions may outperform conventional...
We study modulation spectroscopy of the potassium D2 transitions at 766.7 nm. The vapour pressure, controlled by heating a commercial reference cell, is optimized using conventional saturated absorption spectroscopy. Subsequent heterodyne detection yields sub-Doppler frequency discriminants suitable for stabilizing lasers in experiments with cold atoms. Comparisons are made between spectra obtained direct probe beam, and those transfer from pump via nonlinear mixing. Finally, suggestions...
Cavity quantum electrodynamics describes the fundamental interactions between light and matter, how they can be controlled by shaping local environment. For example, optical microcavities allow high-efficiency detection manipulation of single atoms. In this regime fluctuations atom number are on order mean number, which lead to signal in excess noise incident probe field. Conversely, we demonstrate that nonlinearities multi-atom statistics together serve suppress effects atomic when making...
We predict that an atomic Bose-Einstein condensate strongly coupled to intracavity optical lattice can undergo resonant tunneling and directed transport when a constant uniform bias force is applied. The induces Bloch oscillations, causing amplitude phase modulation of the which resonantly modifies site-to-site tunneling. For right choice parameters net current generated. velocity be oriented oppositely force, with its direction controlled by detuning between pump laser cavity. also enhanced...
We study electromagnetically induced transparency (EIT) in a heated potassium vapor cell, using simple optical setup with single free-running diode laser and an acousto-optic modulator.Despite the fact that Doppler width is comparable to ground state hyperfine splitting, windows deeply sub-natural line widths large group indices are obtained.A longitudinal magnetic field used split EIT feature induce magneto-optical anisotropy.Using beat note between co-propagating coupling probe beams, we...
We present experiments on ensemble cavity quantum electrodynamics with cold potassium atoms in a high-finesse ring cavity. Potassium-39 are cooled two-dimensional magneto-optical trap and transferred to three-dimensional which intersects the mode. The apparatus is described detail first observations of strong coupling presented. Collective light demonstrated via splitting transmission spectrum avoided crossing normal modes.
We consider the equilibration rate for fermions in Bose-Fermi mixtures undergoing cross-dimensional rethermalization. Classical Monte Carlo simulations of relaxation process are performed over a wide range parameters, focusing on effects mass difference between species and degree initial departure from equilibrium. A simple analysis based Enskog's equation is developed shown to be accurate variety different parameter regimes. This allows predictions commonly used alkali atoms.
We analyze the optomechanics of an atomic Bose-Einstein condensate interacting with optical lattice inside a laser-pumped cavity and subject to uniform bias force such as gravity. An wave packet in tilted undergoes Bloch oscillations; backaction atoms on light leads time-dependent modulation intracavity at frequency. When frequency is order damping rate we find transport either up or down lattice. The dynamics can be interpreted manifestation dynamical backaction-induced sideband...
We derive a formula for the light field of monochromatic plane wave that is truncated and reflected by spherical mirror. Within scalar approximation, our valid even deep mirrors, where aperture radius approaches curvature. apply this result to micro-fabricated mirrors whose size scales are in range tens hundreds wavelengths, show sub-wavelength focusing (full-width at half-maximum intensity) can be achieved. This opens up possibility scalable arrays tightly focused optical dipole traps...
The QSNET consortium is building a UK network of next-generation atomic and molecular clocks that will achieve unprecedented sensitivity in testing variations the fine structure constant, $\alpha$, electron-to-proton mass ratio, $\mu$. This turn provide more stringent constraints on wide range fundamental phenomenological theories beyond Standard Model dark matter models.
We demonstrate trapping of individual rubidium (Rb) and cesium (Cs) atoms in an interleaved array bright tweezers dark bottle-beam traps, using a microfabricated optical element illuminated by single laser beam. This approach is simple robust compared to common approaches that use active optoelectronic components multiple wavelengths, can be easily adapted for other atomic species.
We study optical gain in a gas of cold 39K atoms. The is observed during operation conventional magneto-optical trap without the need for additional fields. Measurements transmission spectra from weak probe show that due to stimulated Raman scattering between hyperfine ground states. experimental results are reproduced by simplified six-level model, which also helps explain why such not similar experiments with rubidium or cesium.
We experimentally study the coherence time of a below-threshold Raman laser in which gain medium is gas magneto-optically trapped atoms. The second-order optical exhibits photon bunching with correlation varied by two orders magnitude controlling gain. Results are good agreement simple analytic model suggests effect dominated gain, rather than dispersion, this system. Cavity ring-down measurements show lifetime, related to first-order time, also increased.