ORCID Profile
0000-0001-8627-1298
Current Organisation
Imperial College London
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Publisher: American Physical Society (APS)
Date: 12-2010
Publisher: American Physical Society (APS)
Date: 05-06-2018
Publisher: Springer Science and Business Media LLC
Date: 23-10-2020
DOI: 10.1038/S41534-020-00320-Y
Abstract: Quantum phenomena such as entanglement can improve fundamental limits on the sensitivity of a measurement probe. In optical interferometry, a probe consisting of N entangled photons provides up to a $$\\sqrt{N}$$ N enhancement in phase sensitivity compared to a classical probe of the same energy. Here, we employ high-gain parametric down-conversion sources and photon-number-resolving detectors to perform interferometry with heralded quantum probes of sizes up to N = 8 (i.e. measuring up to 16-photon coincidences). Our probes are created by injecting heralded photon-number states into an interferometer, and in principle provide quantum-enhanced phase sensitivity even in the presence of significant optical loss. Our work paves the way toward quantum-enhanced interferometry using large entangled photonic states.
Publisher: American Physical Society (APS)
Date: 10-01-2022
Publisher: American Physical Society (APS)
Date: 06-08-2020
Publisher: American Physical Society (APS)
Date: 23-05-2008
Publisher: American Physical Society (APS)
Date: 07-09-2018
Publisher: AIP Publishing
Date: 21-05-2012
DOI: 10.1063/1.4719077
Abstract: The initial proposal for scalable optical quantum computing required single photon sources, linear optical elements such as beamsplitters and phaseshifters, and photon detection. Here, we demonstrate a two qubit gate using indistinguishable photons from a quantum dot in a pillar microcavity. As the emitter, the optical circuitry, and the detectors are all semiconductor, this is a promising approach towards creating a fully integrated device for scalable quantum computing.
Publisher: American Physical Society (APS)
Date: 30-09-2022
Publisher: The Optical Society
Date: 10-05-2016
DOI: 10.1364/OE.24.010869
Publisher: AIP Publishing
Date: 13-07-2020
DOI: 10.1063/5.0009681
Abstract: Nonlinear optical microscopy techniques have emerged as a set of successful tools for biological imaging. Stimulated emission microscopy belongs to a small subset of pump–probe techniques, which can image non-fluorescent s les without requiring fluorescent labeling. However, its sensitivity has been shown to be ultimately limited by the quantum fluctuations in the probe beam. We propose and experimentally implement sub-shot-noise limited stimulated emission microscopy by preparing the probe pulse in an intensity-squeezed state. This technique paves the way for imaging delicate biological s les that have no detectable fluorescence with sensitivity beyond standard quantum fluctuations.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 28-01-2022
Abstract: Identifying the boundary beyond which quantum machines provide a computational advantage over their classical counterparts is a crucial step in charting their usefulness. Gaussian boson s ling (GBS), in which photons are measured from a highly entangled Gaussian state, is a leading approach in pursuing quantum advantage. State-of-the-art GBS experiments that run in minutes would require 600 million years to simulate using the best preexisting classical algorithms. Here, we present faster classical GBS simulation methods, including speed and accuracy improvements to the calculation of loop hafnians. We test these on a ∼100,000-core supercomputer to emulate GBS experiments with up to 100 modes and up to 92 photons. This reduces the simulation time for state-of-the-art GBS experiments to several months, a nine–orders of magnitude improvement over previous estimates. Last, we introduce a distribution that is efficient to s le from classically and that passes a variety of GBS validation methods.
Publisher: Springer Science and Business Media LLC
Date: 03-10-2010
DOI: 10.1038/NPHYS1780
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-01-2019
Abstract: Quantum coherence and entanglement offer a quantum advantage, over classical physics, in a randomness processing task.
Publisher: AIP Publishing
Date: 18-01-2010
DOI: 10.1063/1.3294298
Abstract: We report the observation of a Purcell enhancement of the in-plane spontaneous emission rates of InAs self-assembled quantum dots coupled to a mode of a unidirectional photonic crystal waveguide fabricated in GaAs(001). Three-dimensional finite-difference time-domain simulations predict the existence of high quality-factor modes due to the slow light resonances of the waveguide. These modes have been observed experimentally with microphotoluminescence and produce enhanced in-plane emission when resonant with a quantum dot.
Publisher: Optica Publishing Group
Date: 14-01-2022
DOI: 10.1364/OE.450172
Abstract: Multiphoton contributions pose a significant challenge for the realisation of heralded single-photon sources (HSPS) based on nonlinear processes. In this work, we improve the quality of single photons generated in this way by harnessing the photon-number resolving (PNR) capabilities of commercial superconducting nanowire single-photon detectors (SNSPDs). We report a 13 ± 0.4% reduction of g (2) ( τ = 0), even with a collection efficiency in the photon source of only 29.6%. Our work demonstrates the first application of the PNR capabilities of SNSPDs and shows improvement in the quality of an HSPS with widely available technology.
Publisher: IOP Publishing
Date: 03-2011
Publisher: AIP Publishing
Date: 21-07-2014
DOI: 10.1063/1.4891171
Abstract: Colloidal particles are a versatile physical system which have found uses across a range of applications such as the simulation of crystal kinetics, etch masks for fabrication, and the formation of photonic band-gap structures. Utilization of colloidal particles often requires a means to produce highly ordered, periodic structures. One approach is the use of surface acoustic waves (SAWs) to direct the self-assembly of colloidal particles. Previous demonstrations using standing SAWs were shown to be limited in terms of crystal size and dimensionality. Here, we report a technique to improve the spatial alignment of colloidal particles using traveling SAWs. Through control of the radio frequency power, which drives the SAW, we demonstrate enhanced quality and dimensionality of the crystal growth. We show that this technique can be applied to a range of particle sizes in the μm-regime and may hold potential for particles in the sub-μm-regime.
Publisher: American Physical Society (APS)
Date: 17-05-2022
Publisher: SPIE
Date: 07-12-2016
DOI: 10.1117/12.2240833
Publisher: SPIE
Date: 10-02-2011
DOI: 10.1117/12.874630
Publisher: American Physical Society (APS)
Date: 17-10-2019
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-03-2016
Abstract: A quantum controlled-SWAP gate is demonstrated and used to implement small-scale algorithms and produce high-fidelity GHZ states.
Publisher: IOP Publishing
Date: 22-06-2010
DOI: 10.1088/0957-4484/21/27/274011
Abstract: Quantum interference lies at the foundation of many protocols for scalable quantum computing and communication with linear optics. To observe these effects the light source must emit photons that are indistinguishable. From a technological standpoint, it would be beneficial to have electrical control over the emission. Here we report of an electrically driven single-photon source emitting indistinguishable photons. The device consists of a layer of InAs quantum dots embedded in the intrinsic region of a p-i-n diode. Indistinguishability of consecutive photons is tested in a two-photon interference experiment under two modes of operation, continuous and pulsed current injection. We also present a complete theory based on the interference of photons with a Lorentzian spectrum which we compare to both our continuous wave and pulsed experiments. In the former case, a visibility was measured limited only by the timing resolution of our detection system. In the case of pulsed injection, we employ a two-pulse voltage sequence which suppresses multi-photon emission and allows us to carry out temporal filtering of photons which have undergone dephasing. The characteristic Hong-Ou-Mandel 'dip' is measured, resulting in a visibility of 64 +/- 4%.
Publisher: American Physical Society (APS)
Date: 31-08-2018
Publisher: AIP Publishing
Date: 12-05-2008
DOI: 10.1063/1.2918841
Abstract: We generate indistinguishable photons from a semiconductor diode containing an InGaAs/GaAs quantum dot. By using an all-electrical technique to populate and control a single-photon emitting state, we filter out dephasing by Stark shifting the emission energy on time scales below the dephasing time of the state. By mixing consecutive photons on a beam splitter, we observe two-photon interference with a visibility of 64%.
Publisher: SPIE
Date: 12-02-2009
DOI: 10.1117/12.808150
Publisher: AIP
Date: 2011
DOI: 10.1063/1.3630208
Publisher: Springer Science and Business Media LLC
Date: 30-08-2009
DOI: 10.1038/NPHYS1373
Publisher: Springer Science and Business Media LLC
Date: 12-10-2023
Publisher: Optica Publishing Group
Date: 17-05-2021
DOI: 10.1364/OL.421646
Abstract: The discrimination of coherent states is a key task in optical communication and quantum key distribution protocols. In this work, we use a photon-number-resolving detector, the transition-edge sensor, to discriminate binary-phase-shifted coherent states at a telecom wavelength. Owing to its dynamic range and high efficiency, we achieve a bit error probability that unconditionally exceeds the standard quantum limit (SQL) by up to 7.7 dB. The improvement to the SQL persists for signals containing up to approximately seven photons on average and is achieved in a single shot (i.e., without measurement feedback), thus making our approach compatible with larger bandwidths.
Publisher: SPIE
Date: 10-02-2011
DOI: 10.1117/12.872350
Publisher: Springer Science and Business Media LLC
Date: 11-07-2010
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2022
End Date: 2026
Funder: UK Research and Innovation
View Funded Activity