21 results found
Coste N, Gundin M, Fioretto DA, et 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.
Thomas SE, Sagona-Stophel S, Schofield Z, et 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.
Pont M, Albiero R, Thomas SE, et al., 2022, Quantifying n-Photon Indistinguishability with a Cyclic Integrated Interferometer, PHYSICAL REVIEW X, Vol: 12, ISSN: 2160-3308
Thomas SE, Billard M, Coste N, et al., 2021, Bright Polarized Single-Photon Source Based on a Linear Dipole, PHYSICAL REVIEW LETTERS, Vol: 126, ISSN: 0031-9007
Ollivier H, Thomas SE, Wein SC, et al., 2021, Hong-Ou-Mandel Interference with Imperfect Single Photon Sources, PHYSICAL REVIEW LETTERS, Vol: 126, ISSN: 0031-9007
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
Ollivier H, Wenniger IMDB, Thomas S, et al., 2020, Reproducibility of High-Performance Quantum Dot Single-Photon Sources, ACS PHOTONICS, Vol: 7, Pages: 1050-1059, ISSN: 2330-4022
Gao S, Lazo-Arjona O, Brecht B, et al., 2019, Optimal Coherent Filtering for Single Noisy Photons, PHYSICAL REVIEW LETTERS, Vol: 123, ISSN: 0031-9007
Thomas SE, Hird TM, Munns JHD, et al., 2019, Raman quantum memory with built-in suppression of four-wave-mixing noise, PHYSICAL REVIEW A, Vol: 100, ISSN: 2469-9926
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.
Hird TM, Thomas SE, Munns JHD, et 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.
Hird TM, Thomas SE, Munns JHD, et 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.
Kaczmarek KT, Ledingham PM, Brecht B, et 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.
Nunn J, Munns JHD, Thomas S, et al., 2017, Theory of noise suppression in Lambda-type quantum memories by means of a cavity, PHYSICAL REVIEW A, Vol: 96, ISSN: 2469-9926
Thomas SED, Munns JHD, Kaczmarek KT, et al., 2017, High efficiency Raman memory by suppressing radiation trapping, NEW JOURNAL OF PHYSICS, Vol: 19, ISSN: 1367-2630
Kaczmarek KT, Ledingham PM, Brecht B, et 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
Kaczmarek KT, Ledingham PM, Brecht B, et 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.
Ledingham PM, Kaczmarek KT, Brecht B, et 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
Ledingham PM, Kaczmarek KT, Brecht B, et al., 2017, A noiseless quantum optical memory at room temperature
Munns JHD, Thomas SE, Kaczmarek KT, et 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.
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