John Rarity - Academia.edu (original) (raw)

Papers by John Rarity

Abstract The following topics are dealt with: microresonators; photonic molecules; photonic cryst... more Abstract The following topics are dealt with: microresonators; photonic molecules; photonic crystals; optical networks and systems; optical fiber communications; optical fiber devices; fiber lasers and amplifiers; integrated photonic circuits; wavelength-division multiplexing; microwave photonics; and radio-over-fiber networks

... The paper reports on a free space quantum cryptography experiment over a distance of 24.3 ...... more ... The paper reports on a free space quantum cryptography experiment over a distance of 24.3 ... bit error rates , compact modules , error correction , free space quantum cryptography , photon number ... Your institute subscribes to: IEEE/IET Electronic Library (IEL); What can I access? ...

1. Introduction Highly efficient single photon sources with controlled quantum states are attract... more 1. Introduction Highly efficient single photon sources with controlled quantum states are attracting ever growing interest due to their importance in quantum cryptography [1], quantum computation [2] and quantum optics [3]. Here, microcavity pillars with elliptical cross-section are shown ...

Historically non-classical sources of single photons have been used to test quantum mechanics and... more Historically non-classical sources of single photons have been used to test quantum mechanics and to develop the field of quantum optics. Nowadays the single photon source has become a critical device for quantum communications and optical quantum information processing [Knill, et al., 2001]. A single photon source emits one photon at a time, and its quality can be evaluated by three parameters: quantum efficiency, multi-photon probability, and photon distinguishability. Among the different types single photon sources, InGaAs/GaAs quantum dots (QDs) are a promising solid state candidate showing high quantum efficiency, no bleaching effect, long-term stability, capable of high repetition rate, and compatible with standard semiconductor processing techniques. Furthermore, QDs can be embedded in micro-cavities or photonic crystal nano-cavities by in situ growth, and thus cavity quantum electrodynamics (CQED) can be exploited to improve the performance of QD-based single photon sources in all aspects mentioned above [Santori, et al., 2002].

In suspensions containing microspheres and a sub-micron species, such as nanoparticles or a polym... more In suspensions containing microspheres and a sub-micron species, such as nanoparticles or a polymer, an attractive force can result between the microspheres. This attraction arises due to an entropic interaction, often referred to as a depletion force. In this work we demonstrate an application of the depletion force to the controlled assembly of crystalline templates for the production of photonic band gap (PBG) materials. The method makes use of holographic optical tweezers to assemble crystalline arrays of silica or polystyrene microspheres, in which depletion interactions are used to stabilise the structures being built. In addition, we use the holographic optical tweezers to characterise the attraction between pairs of microspheres in the system.

Alberto Politi, Jonathan CF Matthews, Anthony Laing, Alberto Peruzzo, Pruet Kalasuwan, Mian Zhang... more Alberto Politi, Jonathan CF Matthews, Anthony Laing, Alberto Peruzzo, Pruet Kalasuwan, Mian Zhang, Xiao-Qi Zhou, Maria Rodas, Martin J. Cryan, John G. Rarity, Andre Stefanov, Siyuan Yu, Mark G. Thompson and Jeremy L. O'Brien. Centre for Quantum Photonics, HH Wills Physics Laboratory & Department of Electrical and Electronic Engineering, University of Bristol, Merchant Venturers Building, Woodland Road, Bristol, BS8 1UB, UK, Email: Jeremy.OBrien@bristol.ac . Abstract: Quantum technologies based on photons will likely require integrated optics ...

We investigate the spatio-temporal structure of the bi-photon entanglement in parametric downconv... more We investigate the spatio-temporal structure of the bi-photon entanglement in parametric downconversion (PDC) and we demonstrate its non-factorable X-shaped geometry. Such a structure gives access to the ultra-broad bandwidth of PDC, and can be exploited to achieve a bi-photon temporal localization in the femtosecond range. This extreme localization is connected to our ability to resolve the photon positions in the source near-field. The non factorability opens the possibility of tailoring the temporal entanglement by acting on the spatial degrees of freedom of twin photons.

Single photons are at the heart of optical quantum technologies such as quantum cryptography, qua... more Single photons are at the heart of optical quantum technologies such as quantum cryptography, quantum computing and quantum metrology. In this paper we report on the creation of photon pairs via four-wave-mixing (FWM) in birefringent photonic crystal fibres (PCF). It has recently been suggested that for thoroughly engineering the phase matching condition of a birefringent PCF, photon pairs can by

Quantum technologies based on photons will likely require integrated optics architectures for imp... more Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits and the first integrated quantum algorithm.

Quantum technologies based on photons will likely require integrated optics architectures for imp... more Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits and the first integrated quantum algorithm.

This paper uses the plane-wave expansion and finite-difference time-domain methods to study tunab... more This paper uses the plane-wave expansion and finite-difference time-domain methods to study tunable 3D photonic crystals for use in display applications. The paper calculates particle diameter and refractive index for operation across the visible spectrum and estimates the reflectivity achievable for one to five layers of particles. The effects of disorder in particle position and diameter are then studied and the results show the system to be robust against such effects. Finally, the paper discusses the potential performance of this display technology in terms of reflectivity, color gamut, and contrast ratio.

Optically active 'color' centers in diamond may be individually... more Optically active 'color' centers in diamond may be individually addressed using standard confocal fluorescence mi-croscopy techniques, allowing optical access to a solid state quantum system, with several species capable of room temperature stable single photon emission. ...

Abstract Optical quantum technologies require new photonic components to exploit integrated archi... more Abstract Optical quantum technologies require new photonic components to exploit integrated architecture. We demonstrate quantum interference in MMI couplers and coupled waveguides that implement two-particle quantum walks, showing unique quantum behaviour.

Understanding far and close proximity human-human interaction observed from a distance is a neces... more Understanding far and close proximity human-human interaction observed from a distance is a necessary step towards automated suspicious or antisocial behaviour detection. Most previous work on human-human interaction has made the implicit assumption that interactions occur only at immediate spatial and temporal proximity between the subjects concerned. We propose a more realistic application of human-human interaction detection from surveillance data where the subjects of interest tend to be represented by few pixels ...

We present a simple but highly efficient source of polarization-entangled photons based on sponta... more We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phasematching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.

Abstract The following topics are dealt with: microresonators; photonic molecules; photonic cryst... more Abstract The following topics are dealt with: microresonators; photonic molecules; photonic crystals; optical networks and systems; optical fiber communications; optical fiber devices; fiber lasers and amplifiers; integrated photonic circuits; wavelength-division multiplexing; microwave photonics; and radio-over-fiber networks

... The paper reports on a free space quantum cryptography experiment over a distance of 24.3 ...... more ... The paper reports on a free space quantum cryptography experiment over a distance of 24.3 ... bit error rates , compact modules , error correction , free space quantum cryptography , photon number ... Your institute subscribes to: IEEE/IET Electronic Library (IEL); What can I access? ...

1. Introduction Highly efficient single photon sources with controlled quantum states are attract... more 1. Introduction Highly efficient single photon sources with controlled quantum states are attracting ever growing interest due to their importance in quantum cryptography [1], quantum computation [2] and quantum optics [3]. Here, microcavity pillars with elliptical cross-section are shown ...

Historically non-classical sources of single photons have been used to test quantum mechanics and... more Historically non-classical sources of single photons have been used to test quantum mechanics and to develop the field of quantum optics. Nowadays the single photon source has become a critical device for quantum communications and optical quantum information processing [Knill, et al., 2001]. A single photon source emits one photon at a time, and its quality can be evaluated by three parameters: quantum efficiency, multi-photon probability, and photon distinguishability. Among the different types single photon sources, InGaAs/GaAs quantum dots (QDs) are a promising solid state candidate showing high quantum efficiency, no bleaching effect, long-term stability, capable of high repetition rate, and compatible with standard semiconductor processing techniques. Furthermore, QDs can be embedded in micro-cavities or photonic crystal nano-cavities by in situ growth, and thus cavity quantum electrodynamics (CQED) can be exploited to improve the performance of QD-based single photon sources in all aspects mentioned above [Santori, et al., 2002].

In suspensions containing microspheres and a sub-micron species, such as nanoparticles or a polym... more In suspensions containing microspheres and a sub-micron species, such as nanoparticles or a polymer, an attractive force can result between the microspheres. This attraction arises due to an entropic interaction, often referred to as a depletion force. In this work we demonstrate an application of the depletion force to the controlled assembly of crystalline templates for the production of photonic band gap (PBG) materials. The method makes use of holographic optical tweezers to assemble crystalline arrays of silica or polystyrene microspheres, in which depletion interactions are used to stabilise the structures being built. In addition, we use the holographic optical tweezers to characterise the attraction between pairs of microspheres in the system.

Alberto Politi, Jonathan CF Matthews, Anthony Laing, Alberto Peruzzo, Pruet Kalasuwan, Mian Zhang... more Alberto Politi, Jonathan CF Matthews, Anthony Laing, Alberto Peruzzo, Pruet Kalasuwan, Mian Zhang, Xiao-Qi Zhou, Maria Rodas, Martin J. Cryan, John G. Rarity, Andre Stefanov, Siyuan Yu, Mark G. Thompson and Jeremy L. O'Brien. Centre for Quantum Photonics, HH Wills Physics Laboratory & Department of Electrical and Electronic Engineering, University of Bristol, Merchant Venturers Building, Woodland Road, Bristol, BS8 1UB, UK, Email: Jeremy.OBrien@bristol.ac . Abstract: Quantum technologies based on photons will likely require integrated optics ...

We investigate the spatio-temporal structure of the bi-photon entanglement in parametric downconv... more We investigate the spatio-temporal structure of the bi-photon entanglement in parametric downconversion (PDC) and we demonstrate its non-factorable X-shaped geometry. Such a structure gives access to the ultra-broad bandwidth of PDC, and can be exploited to achieve a bi-photon temporal localization in the femtosecond range. This extreme localization is connected to our ability to resolve the photon positions in the source near-field. The non factorability opens the possibility of tailoring the temporal entanglement by acting on the spatial degrees of freedom of twin photons.

Single photons are at the heart of optical quantum technologies such as quantum cryptography, qua... more Single photons are at the heart of optical quantum technologies such as quantum cryptography, quantum computing and quantum metrology. In this paper we report on the creation of photon pairs via four-wave-mixing (FWM) in birefringent photonic crystal fibres (PCF). It has recently been suggested that for thoroughly engineering the phase matching condition of a birefringent PCF, photon pairs can by

Quantum technologies based on photons will likely require integrated optics architectures for imp... more Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits and the first integrated quantum algorithm.

Quantum technologies based on photons will likely require integrated optics architectures for imp... more Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits and the first integrated quantum algorithm.

This paper uses the plane-wave expansion and finite-difference time-domain methods to study tunab... more This paper uses the plane-wave expansion and finite-difference time-domain methods to study tunable 3D photonic crystals for use in display applications. The paper calculates particle diameter and refractive index for operation across the visible spectrum and estimates the reflectivity achievable for one to five layers of particles. The effects of disorder in particle position and diameter are then studied and the results show the system to be robust against such effects. Finally, the paper discusses the potential performance of this display technology in terms of reflectivity, color gamut, and contrast ratio.

Optically active 'color' centers in diamond may be individually... more Optically active 'color' centers in diamond may be individually addressed using standard confocal fluorescence mi-croscopy techniques, allowing optical access to a solid state quantum system, with several species capable of room temperature stable single photon emission. ...

Abstract Optical quantum technologies require new photonic components to exploit integrated archi... more Abstract Optical quantum technologies require new photonic components to exploit integrated architecture. We demonstrate quantum interference in MMI couplers and coupled waveguides that implement two-particle quantum walks, showing unique quantum behaviour.

Understanding far and close proximity human-human interaction observed from a distance is a neces... more Understanding far and close proximity human-human interaction observed from a distance is a necessary step towards automated suspicious or antisocial behaviour detection. Most previous work on human-human interaction has made the implicit assumption that interactions occur only at immediate spatial and temporal proximity between the subjects concerned. We propose a more realistic application of human-human interaction detection from surveillance data where the subjects of interest tend to be represented by few pixels ...

We present a simple but highly efficient source of polarization-entangled photons based on sponta... more We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by a 405 nm laser diode. Utilizing one of the highest available nonlinear coefficients in a non-degenerate, collinear type-0 phasematching configuration, we generate polarization entanglement via the crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an overlap fidelity with the ideal Bell state of 0.98 at a pump power of 0.025 mW.