A5051152836- Cold Atom Physics and Bose-Einstein Condensates
- Photonic and Optical Devices
- Quantum Information and Cryptography
- Photonic Crystals and Applications
- Quantum optics and atomic interactions
- Spectroscopy and Laser Applications
- Advanced Frequency and Time Standards
- Orbital Angular Momentum in Optics
- Atomic and Subatomic Physics Research
- Advanced Fiber Optic Sensors
- Advanced Fiber Laser Technologies
- Semiconductor Lasers and Optical Devices
- Plasmonic and Surface Plasmon Research
- Mechanical and Optical Resonators
- Silicon Nanostructures and Photoluminescence
- Optical Coatings and Gratings
- Advanced Semiconductor Detectors and Materials
- Fern and Epiphyte Biology
- Nanoplatforms for cancer theranostics
- Advanced X-ray and CT Imaging
- Porphyrin and Phthalocyanine Chemistry
- Textile materials and evaluations
- Near-Field Optical Microscopy
- Quantum Mechanics and Applications
- History and advancements in chemistry
Okinawa Institute of Science and Technology Graduate University
2013-2017
University of Sheffield
2012-2014
Munster Technological University
2005-2011
University College Cork
2009-2011
International Energy Research Centre
2007-2010
Institute of Spectroscopy
2009
National University of Ireland
2006
We describe a reproducible method of fabricating adiabatic tapers with 3–4μm diameter. The is based on heat-and-pull rig, whereby CO2 laser continuously scanned across length fiber that being pulled synchronously. Our system relies mirror mounted geared stepper motor in order to scan the beam taper region. show this offers reliable alternative more traditional rigs incorporating galvanometer scanners. have routinely obtained transmission losses between 0.1 and 0.3dB indicating satisfactory...
We present a novel technique for measuring the characteristics of magneto-optical trap (MOT) cold atoms by monitoring spontaneous emission from trapped coupled into guided mode tapered optical nanofiber. show that nanofiber is highly sensitive to very small numbers close its surface. The size and shape MOT, determined translating atom cloud across fiber, in excellent agreement with measurements obtained using conventional method fluorescence imaging charge device camera. coupling atomic...
We experimentally demonstrate a new optical filter design based on vertically coupled photonic crystal (PhC) cavity and bus waveguide monolithically integrated the silicon-on-insulator platform. The use of gives flexibility in choice material dimensions, dramatically lowering insertion loss while achieving very high coupling efficiencies to wavelength scale resonators thus allows creation PhC-based filters with extinction ratio (>10 dB).
We propose an optical dipole trap for cold neutral atoms based on the electric field produced from evanescent fields in a hollow rectangular slot cut through nanofibre. In particular, we discuss performance relation to laser-cooled rubidium and show that far off-resonance, blue-detuned combined with attractive surface-atom interaction potential dielectric material forms stable trapping configuration. With addition of red-detuned field, demonstrate how three dimensional confinement at...
Optical nanofibres are used to confine light sub-wavelength regions and very promising tools for the development of optical fibre-based quantum networks using cold, neutral atoms. To date, experimental studies on atoms near have focussed fundamental fibre mode interactions. In this work, we demonstrate integration a few-mode nanofibre into magneto-optical trap 87Rb The nanofibre, with waist diameter ∼700 nm, supports both first group higher order modes (HOMs) is atomic fluorescence...
The precision and efficacy of photodynamic therapy (PDT) is essential for the treatment brain tumors because cancer cells are within or adjacent to delicate nervous system. Taurine an abundant amino acid in that serves central system (CNS). A taurine-modified polypyridyl Ru-complex was shown have optimized intracellular affinity through accumulation lysosomes. Symmetrical modification this by multiple taurine molecules enhanced efficiency molecular emission with boosted generation reactive...
The tight confinement of the evanescent light field around waist an optical nanofiber makes it a suitable tool for studying nonlinear optics in atomic media. Here, we use embedded cloud laser-cooled $^{87}\mathrm{Rb}$ near-infrared frequency up-conversion via resonant two-photon process. Sub-nW powers radiation, at 780 and 776 nm, copropagate through generation 420 nm photons is observed. A measurement Autler-Townes splitting provides direct Rabi transition. Through this method, dephasings...
We present a method for measuring the average temperature of cloud cold 85Rb atoms in magneto-optical trap using an optical nanofibre. A periodic spatial variation is applied to magnetic fields generated by trapping coils and this causes centre oscillate, which, turn, oscillate. The nanofibre used collect fluorescence emitted atoms, frequency response between motion oscillating determined. This allows us make measurements both above below Doppler limit, thereby paving way nanofibres be...
An optical printing technique is used to accurately position a 150 nm diameter gold nanoparticle onto submicrometer linear three‐hole defect of photonic crystal nanocavity. It shown (using both experiment and finite‐difference time domain modelling), that there an electromagnetic interaction between the cavity mode, with field within being dissipated by driving plasmon resonance. The use selectively nanoparticles surface‐accessible potentially allows hybridisation electronic, excitonic,...
The application of a silicon-nitride based L3 optical nanocavity as chemical sensor is explored. It shown that by adjusting the thickness an ultra-thin Lumogen Red film deposited onto surface, fundamental mode undergoes progressive red-shift layer-thickness increases, with cavity being able to detect presence single molecular monolayer. properties whose surface coated thin layer porphyrin-based polymer are also On exposure acidic-vapour, it changes in porphyrin-film (thickness and refractive...
We report on the observation of a Zeeman shift (order 100 MHz) Doppler-broadened D<sub>2</sub> transition both <sup>85</sup>Rb and <sup>87</sup>Rb isotopes via transmission through 400 nm diameter optical nanofiber in presence DC magnetic field. Linearly-polarized light propagating is analyzed as superposition two orthogonally circularly polarized orientations, σ+ σ-. In absence field, absorption these polarizations by atomic vapor, evanescent field at waist nanofiber,...
One of the most important characteristics for controlling processes on quantum scale is fidelity or robustness techniques being used. In case single atoms localized in micro-traps, it was recently shown that use time-dependent tunnelling interactions a multi-trap setup can be viewed as analogous to area multi-level optics. The atom's centre-of-mass then controlled with high fidelity, using STIRAP-type process. Here, we review previous work led development atom optics and present two examples...
Integration density, channel scalability, low switching energy and insertion loss are the major prerequisites for on-chip WDM systems. A number of device geometries have already been demonstrated that fulfill these criteria, at least in part, but combining all requirements is still a difficult challenge. I will present our recent work on photonic crystal enhanced light sources, modulators detectors silicon photonics, promise to give ultimate area consumption.
We experimentally demonstrate a new optical filter design comprising of photonic crystal cavity and low index bus waveguide which are monolithically integrated on silicon-on-insulator (SOI) platform. have fabricated oxide clad PhC cavities with silicon nitride positioned directly above, such that there is an overlap between the evanescent tails two modes. realised extinction ratio 7.5dB for total Q 50,000.
Single gold nanoparticles are accurately positioned onto a submicrometer linear three-hole photonic crystal nanocavity by J. Rodríguez-Fernández, Feldmann, D. G. Lidzey, and co-workers via an optical printing technique. On page 946, this leads to significant electromagnetic interaction between the cavity mode nanoparticles' localized surface plasmon in hybrid structure. The versatile scalable nature of approach enables routine construction new types devices sensors. Cover Christoph Hohmann,...
Research interest in designing sources of cold atoms has significantly increased during the past ten years with development suitable laser for magneto-optical trapping and further mastering evaporative cooling order to achieve Bose-Einstein condensation. The trap is now viewed as a standard research facility worldwide opened up many new exciting directions atomic physics. One area that combining spherical microcavities efficient photon exchange between cavity atom understandings quantum...
In this paper, the interaction between cold rubidium atoms in a magneto-optical trap (MOT) and evanescent field of sub-micron fibre is studied. The taper fabricated from 780 nm single mode using heat-and-pull rig with CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> laser heat source.
We present a method for the controlled and robust generation of spatial superposition states single atoms in micro-traps. Using counter-intuitive positioning sequence individual potentials appropriately chosen trapping frequencies, we show that it is possible to selectively create two different orthogonal states, which can turn be used quantum information purposes.
We present initial results obtained using an evanescent field of a tapered optical fibre for trapping and guiding cold, neutral atoms. Losses through the are monitored in order to detect atom-light coupling.
We demonstrate excitation of higher order modes in an optical nanofiber by resonantly-excited 87Rb atoms. Absorption laser-cooled atoms is enhanced when probe light propagates compared to the fundamental mode.
We have developed a compact hard X-ray imaging system composed of cadmium telluride double-sided strip detector (CdTe-DSD) and coded mask. investigate the performance using two different masks with sizes patterns. In our system, CdTe-DSD pitch 250μm is used in conjunction mask placed 70-100 mm above to form system. obtained an angular resolution up 11.8 arc min, as measured from gamma-ray lines point-like radioactive isotope sources. This consistent that expected geometry. The energy 1.7 keV...