Imperial College London

DrSarahThomas

Faculty of Natural SciencesDepartment of Physics

Imperial College Research Fellow
 
 
 
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Contact

 

s.thomas14

 
 
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Location

 

204Royal College of ScienceSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

21 results found

Coste N, Gundin M, Fioretto DA, Thomas SE, Millet C, Mehdi E, Somaschi N, Morassi M, Pont M, LemaƮtre A, Belabas N, Krebs O, Lanco L, Senellart Pet al., 2023, Probing the dynamics and coherence of a semiconductor hole spin via acoustic phonon-assisted excitation, Quantum Science and Technology, Vol: 8

Spins in semiconductor quantum dots (QDs) are promising local quantum memories to generate polarization-encoded photonic cluster states, as proposed in the pioneering Lindner and Rudolph scheme (2009 Phys. Rev. Lett. 103 113602). However, harnessing the polarization degree of freedom of the optical transitions is hindered by resonant excitation schemes that are widely used to obtain high photon indistinguishability. Here we show that acoustic phonon-assisted excitation, a scheme that preserves high indistinguishability, also allows to fully exploit the polarization selective optical transitions to initialise and measure single spin states. We access the coherence of hole spin systems in a low transverse magnetic field and directly monitor the spin Larmor precession both during the radiative emission process of an excited state or in the QD ground state. We report a spin state detection fidelity of 94.7±0.2% granted by the optical selection rules and a 25±5 ns hole spin coherence time, demonstrating the potential of this scheme and system to generate linear cluster states with a dozen of photons.

Journal article

Thomas SE, Sagona-Stophel S, Schofield Z, Walmsley IA, Ledingham PMet al., 2023, Single-Photon-Compatible Telecommunications-Band Quantum Memory in a Hot Atomic Gas, Physical Review Applied, Vol: 19

The efficient storage and on-demand retrieval of quantum optical states that are compatible with the telecommunications band is a requirement for future terrestrial-based quantum optical networking. Spectrum in the telecommunications band minimizes optical fiber-propagation losses, and broad optical bandwidth facilitates high-speed networking protocols. Here we report on a telecommunications-wavelength- and bandwidth-compatible quantum memory. Using the Off-Resonant Cascaded Absorption protocol in hot 87Rb vapor, we demonstrate a total internal memory efficiency of 20.90(1)% with a Doppler-limited storage time of 1.10(2) ns. We characterize the memory performance with weak coherent states and measure a signal-to-noise ratio of 1.9(1)×104 for an average input photon number of 0.084.

Journal article

Pont M, Albiero R, Thomas SE, Spagnolo N, Ceccarelli F, Corrielli G, Brieussel A, Somaschi N, Huet H, Harouri A, Lemaitre A, Sagnes I, Belabas N, Sciarrino F, Osellame R, Senellart P, Crespi Aet al., 2022, Quantifying n-Photon Indistinguishability with a Cyclic Integrated Interferometer, PHYSICAL REVIEW X, Vol: 12, ISSN: 2160-3308

Journal article

Thomas SE, Billard M, Coste N, Wein SC, Priya, Ollivier H, Krebs O, Tazairt L, Harouri A, Lemaitre A, Sagnes I, Anton C, Lanco L, Somaschi N, Loredo JC, Senellart Pet al., 2021, Bright Polarized Single-Photon Source Based on a Linear Dipole, PHYSICAL REVIEW LETTERS, Vol: 126, ISSN: 0031-9007

Journal article

Ollivier H, Thomas SE, Wein SC, Wenniger IMDB, Coste N, Loredo JC, Somaschi N, Harouri A, Lemaitre A, Sagnes I, Lanco L, Simon C, Anton C, Krebs O, Senellart Pet al., 2021, Hong-Ou-Mandel Interference with Imperfect Single Photon Sources, PHYSICAL REVIEW LETTERS, Vol: 126, ISSN: 0031-9007

Journal article

Thomas S, Senellart P, 2021, The race for the ideal single-photon source is on, NATURE NANOTECHNOLOGY, Vol: 16, Pages: 367-368, ISSN: 1748-3387

Journal article

Ollivier H, Wenniger IMDB, Thomas S, Wein S, Coppola G, Harouri A, Hilaire P, Millet C, Lemaitre A, Sagnes I, Krebs O, Lanco L, Loredo JC, Anton C, Somaschi N, Senellart Pet al., 2020, Reproducibility of High-Performance Quantum Dot Single-Photon Sources, ACS PHOTONICS, Vol: 7, Pages: 1050-1059, ISSN: 2330-4022

Journal article

Gao S, Lazo-Arjona O, Brecht B, Kaczmarek KT, Thomas SE, Nunn J, Ledingham PM, Saunders DJ, Walmsley IAet al., 2019, Optimal Coherent Filtering for Single Noisy Photons, PHYSICAL REVIEW LETTERS, Vol: 123, ISSN: 0031-9007

Journal article

Thomas SE, Hird TM, Munns JHD, Brecht B, Saunders DJ, Nunn J, Walmsley IA, Ledingham PMet al., 2019, Raman quantum memory with built-in suppression of four-wave-mixing noise, PHYSICAL REVIEW A, Vol: 100, ISSN: 2469-9926

Journal article

Gao S, Lazo-Arjona O, Brecht B, Kaczmarek KT, Ledingham PM, Thomas SE, Nunn J, Saunders DJ, Walmsley IAet al., 2019, Optimal coherent filtering for single photons

We propose a quantum buffer which optimally filters the temporal-spectral mode of single photon source. We theoretically show that using a Cs vapour, an increase of indistinguishably with minimal loss of brightness can be achieved.

Conference paper

Hird TM, Thomas SE, Munns JHD, Brecht B, Saunders DJ, Nunn J, Walmsley IA, Ledingham PMet al., 2019, Noise suppression via atomic absorption in a Raman quantum memory

We demonstrate strong suppression of noise on the output of a Raman quantum memory.

Conference paper

Kaczmarek KT, Ledingham PM, Brecht B, Thomas SE, Thekkadath GS, Lazo-Arjona O, Munns JHD, Poem E, Feizpour A, Saunders DJ, Nunn J, Walmsley IAet al., 2018, High-speed noise-free optical quantum memory, PHYSICAL REVIEW A, Vol: 97, ISSN: 2469-9926

Journal article

Hird TM, Thomas SE, Munns JHD, Arjona OL, Gao S, Nunn J, Brecht B, Saunders DJ, Ledingham PM, Walmsley IAet al., 2018, Engineering a noiseless and broadband Raman quantum memory for temporal mode manipulation

The Raman quantum memory can manipulate temporal modes of light - a promising high-dimensional basis for quantum information processing. We demonstrate both temporal mode manipulation and a novel suppression scheme for four-wave mixing noise.

Conference paper

Kaczmarek KT, Ledingham PM, Brecht B, Feizpour A, Thekkadath GS, Thomas SE, Munns JHD, Saunders DJ, Walmsley IA, Nunn Jet al., 2017, QLad: A noise-free quantum memory for broadband light at room temperature, Pages: 1-2

We implement a low-noise, broadband quantum memory for light via off-resonant two-photon absorption in warm atomic vapour. We store heralded single photons and verify that the retrieved fields are anti-bunched.

Conference paper

Nunn J, Munns JHD, Thomas S, Kaczmarek KT, Qiu C, Feizpour A, Poem E, Brecht B, Saunders DJ, Ledingham PM, Reddy DV, Raymer MG, Walmsley IAet al., 2017, Theory of noise suppression in Lambda-type quantum memories by means of a cavity, PHYSICAL REVIEW A, Vol: 96, ISSN: 2469-9926

Journal article

Thomas SED, Munns JHD, Kaczmarek KT, Qiu C, Brecht B, Feizpour A, Ledingham PM, Walmsley IA, Nunn J, Saunders DJet al., 2017, High efficiency Raman memory by suppressing radiation trapping, NEW JOURNAL OF PHYSICS, Vol: 19, ISSN: 1367-2630

Journal article

Kaczmarek KT, Ledingham PM, Brecht B, Feizpour A, Thekkadath GS, Thomas SE, Munns JHD, Saunders DJ, Walmsley IA, Nunn Jet al., 2017, QLad: A Noise-Free Quantum Memory for Broadband Light at Room Temperature, Conference on Lasers and Electro-Optics (CLEO), Publisher: IEEE, ISSN: 2160-9020

Conference paper

Kaczmarek KT, Ledingham PM, Brecht B, Feizpour A, Thekkadath GS, Thomas SE, Munns JHD, Saunders DJ, Walmsley IA, Nunn Jet al., 2017, A noise-free quantum memory for broadband light at room temperature

We have developed a novel protocol for broadband, noise-free light-matter interactions using off-resonant two-photon absorption. We have successfully stored and retrieved 1.5 GHz bandwidth heralded single photons in warm cesium vapour, measuring a g(2)h = 0:39±0:05.

Conference paper

Ledingham PM, Kaczmarek KT, Brecht B, Feizpour A, Thekkadath GS, Thomas SE, Munns JHD, Saunders DJ, Nunn J, Walmsley IAet al., 2017, A Noiseless Quantum Optical Memory at Room Temperature, Conference on Lasers and Electro-Optics Europe / European Quantum Electronics Conference (CLEO/Europe-EQEC), Publisher: IEEE

Conference paper

Ledingham PM, Kaczmarek KT, Brecht B, Feizpour A, Thekkadath GS, Thomas SE, Munns JHD, Saunders DJ, Nunn J, Walmsley IAet al., 2017, A noiseless quantum optical memory at room temperature

Conference paper

Munns JHD, Thomas SE, Kaczmarek KT, Ledingham PM, Saunders DJ, Nunn J, Brecht B, Walmsley IAet al., 2017, Temporal-mode selection with a Raman quantum memory

Temporal modes (TMs) of pulsed single-photon states have been identified as appealing basis states for quantum information science. Recent work has seen progress towards TM-selective operations based on nonlinear optics. Here, we demonstrate for the first time a linear TM-selective device, namely a Raman quantum memory in warm atomic Caesium vapour. We achieve switching fidelities of 86.5% when operating the memory with ns-duration pulses. These results pave the way towards new quantum information applications, where TM-selection, TM-reshaping, and network synchronisation are achieved with one single device.

Conference paper

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