A5017198574- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Spectroscopy and Laser Applications
- Advanced Frequency and Time Standards
- Quantum optics and atomic interactions
- Laser Design and Applications
- Quantum Information and Cryptography
- Atmospheric and Environmental Gas Dynamics
- Mechanical and Optical Resonators
- Atmospheric Ozone and Climate
- Electronic and Structural Properties of Oxides
- Analytical Chemistry and Sensors
- Photonic and Optical Devices
- Spectroscopy and Quantum Chemical Studies
- Geophysics and Sensor Technology
- Analytical Chemistry and Chromatography
- Quantum Mechanics and Applications
- Calibration and Measurement Techniques
- Advanced Sensor Technologies Research
- Ocular Infections and Treatments
- RFID technology advancements
- Wireless Power Transfer Systems
- Color Science and Applications
- Semiconductor materials and devices
- Magnetic Field Sensors Techniques
University of Nottingham
2010-2024
University of Sussex
2019
University of Copenhagen
2007-2010
Danish National Research Foundation
2008-2010
University of Amsterdam
2006-2008
Heidelberg University
2000-2007
Institute of Physical Chemistry
2001
University College Cork
1998
We present what is to our knowledge the first near-infrared diode-laser-based absorption spectrometer that suitable for simultaneous in situ measurement of carbon monoxide, water vapor, and temperature combustion chamber (20-m diameter, 13-m path length) a 600-MW lignite-fired power plant. A fiber-coupled distributed-feedback diode-laser module at 1.56 microm served CO detection, Fabry-Perot diode laser 813 nm was used determine H2O concentrations from multiline spectra. Despite severe light...
We demonstrate spin squeezing in a room temperature ensemble of $\ensuremath{\approx}{10}^{12}$ cesium atoms using their internal structure, where the necessary entanglement is created between nuclear and electronic spins each individual atom. This state provides improvement measurement sensitivity beyond standard quantum limit for memory experiments applications metrology thus complementary alternative to obtained via interatom entanglement. Squeezing collective verified by tomography.
Arrays of trapped atoms are the ideal starting points for developing registers comprising large numbers physical qubits storing and processing quantum information. One very promising approach involves neutral atom traps produced on microfabricated devices known as chips, almost arbitrary trap configurations can be realized in a robust compact package. Until now, however, chip experiments have focused small systems incorporating single or only few individual traps. Here, we report...
We present two novel matter-wave Sagnac interferometers based on ring- shaped time-averaged adiabatic potentials (TAAP). For both the atoms are put into a superposition of different spin states and manipulated independently using elliptically polarized rf-fields. In first interferometer accelerated by spin-state-dependent forces then travel around ring in guide. second one fully trapped during entire interferometric sequence moved "buckets". Corrections to ideal phase investigated for cases....
The Sagnac effect enables interferometric measurements of rotation with high precision. Using matter waves instead light promises resolution enhancement by orders magnitude that scales particle mass. So far, the paradigm for wave interferometry relies on de Broglie and thus free propagation atoms either in fall or within waveguides. However, can be expressed as a proper time difference experienced two observers moving opposite directions along closed paths has indeed been measured atomic...
Neutral atoms can be trapped and manipulated with surface mounted microscopic current carrying charged structures. We present a lithographic fabrication process for such atom chips based on evaporated metal films. The size limit of this is below 1 μm. At room temperature, thin wires carry densities more than 107A∕cm2 voltages 500 V. Extensive test measurements different substrates thicknesses (up to 5 μm) are compared models the heating characteristics wires. Among materials tested, we find...
A new lightweight near-infrared tunable diode laser spectrometer CHILD (Compact High-altitude In-situ Laser Diode spectrometer) was developed for flights to the stratosphere as an additional in situ sensor on existing balloonborne payloads. Free-air absorption measurements near infrared are made with open-path Herriott cell design features. It offers two individual path lengths optimized CH4 74 m (136 pass) and H2O 36 (66 pass). New electronic features include a real-time gain control loop...
We have realized a two-dimensional permanent magnetic lattice of Ioffe-Pritchard microtraps for ultracold atoms. The is formed by single $300\text{\ensuremath{-}}\mathrm{nm}$ magnetized layer FePt, patterned using optical lithography. Our consists more than 15 000 tightly confining with density $1250\phantom{\rule{0.3em}{0ex}}\text{traps}∕{\mathrm{mm}}^{2}$. Simple analytical approximations the fields produced are used to derive relevant trap parameters. load atoms into at least 30 sites...
Collisions, even though they do not limit the lifetime of quantum information stored in ground-state hyperfine coherences, may severely fidelity for memory when happen during write and read process. This imposes restrictions on implementation Raman-type processes thermal vapor cells their performance as a memory. We study effect these collisions our experiment.
We present traps with toroidal $({T}^{2})$ and ring-shaped topologies based on adiabatic potentials for radio-frequency-dressed Zeeman states in a magnetic quadrupole field. Simple adjustment of the radio-frequency fields provides versatile possibilities dynamical parameter tuning, topology change, controlled potential perturbation. show how to induce poloidal rotations, demonstrate feasibility preparing degenerate quantum gases reduced dimensionality periodic boundary conditions. The great...
We present an experimental investigation of alkali atom vapor cells coated with a high quality anti-relaxation coating material based on alkenes. The prepared single compound alkene showed the longest spin relaxation times which have been measured up to now room temperature cells. Suggestions are made that chemical binding cesium and molecule by attack C=C bond plays crucial role in such improvement quality.
The dynamics of excitons in a one-dimensional ensemble with partial spatial order are studied. During optical excitation, cold Rydberg atoms spontaneously organize into regular arrangements due to their mutual interactions. This emergent lattice is used as the starting point study resonant energy transfer triggered by driving $nS$ ${n}^{\ensuremath{'}}P$ transition using microwave field. probed detecting survival probability state. Experimental data qualitatively agree our theoretical...
We analyse a novel squeezing and entangling mechanism which is due to correlated Stokes anti-Stokes photon forward scattering in multi-level atom vapour. develop full quantum model for an alkali atomic vapour including quantized collective states predicts high degree of attainable experimental conditions. Following the proposal we present demonstration 3.5 dB pulsed frequency nondegenerate squeezed (quadrature entangled) state light using room temperature caesium The source very robust...
We describe a method to dispersively detect all three vector components of an external magnetic field using alkali-metal atoms based on the Voigt effect. Our relies measuring linear birefringence radio-frequency dressed atomic medium via polarization homodyning. This gives rise modulated signals at first and second harmonic dressing frequency. The are mapped onto quadratures these harmonics. find that our scheme can be utilized in both cold hot gases such fields shielded unshielded...
We describe a proof-of-principle experiment on fully permanent magnet atom chip. study ultracold atoms and produce Bose-Einstein condensate. The magnetic trap is loaded efficiently by adiabatic transport of via the application uniform external fields. Radio frequency spectroscopy used for in-trap analysis to determine temperature atomic cloud. formation condensate observed in time-of-flight images as narrow peak appearing radio spectrum.
We experimentally investigate the properties of radio-frequency-dressed potentials for Bose-Einstein condensates on atom chips. The three-dimensional potential forms a connected pair parallel waveguides. show that rf-dressed are robust against effect small magnetic-field variations trap potential. Long-lived dipole oscillations induced in can be tuned to remarkably low damping rate. study beam-splitter and propagating condensate dynamically split two vertically separated parts guided along...
The UK National Quantum Technology Hub in Sensors and Metrology is one of four flagship initiatives the Program. As part a 20-year vision it translates laboratory demonstrations to deployable practical devices, with game-changing miniaturized components prototypes that transform state-of-the-art for quantum sensors metrology. It brings together experts from Universities Birmingham, Glasgow, Nottingham, Southampton, Strathclyde Sussex, NPL currently links over 15 leading international...
We introduce a method to dispersively detect alkali atoms in radio-frequency dressed states. In particular, we use detection measure populations and population differences of prepared their clock Linear birefringence the atomic medium enables atom number via polarisation homodyning, form common path interferometry. order achieve low technical noise levels, perform optical sideband after adiabatic transformation bare states into The balanced homodyne signal then oscillates independently field...
We study the hyperfine spectrum of atoms $^{87}\mathrm{Rb}$ dressed by a radio-frequency field and present experimental results in three different situations: freely falling atoms, trapped an optical dipole trap, adiabatic shell trap. In all cases, we observe several resonant sidebands spaced (in frequency) at intervals equal to dressing frequency, corresponding transitions enabled field. theoretically explain main features microwave using semiclassical model low-field limit rotating-wave...