arXiv:1409.2892 · Physical Review Letters

Storage and Retrieval of THz-Bandwidth Single Photons Using a Room-Temperature Diamond Quantum Memory

Duncan G. England, Kent Bonsma-Fisher, Jean-Philippe W. MacLean, Philip J. Bustard, Rune Lausten, Kevin J. Resch, Benjamin Sussman

Published Feb 5, 2015• 115 citations

arXiv HTML PDF

Abstract

We report the storage and retrieval of single photons, via a quantum memory, in the optical phonons of a room-temperature bulk diamond. The THz-bandwidth heralded photons are generated by spontaneous parametric down-conversion and mapped to phonons via a Raman transition, stored for a variable delay, and released on demand. The second-order correlation of the memory output is g((2))(0)=0.65±0.07, demonstrating a preservation of nonclassical photon statistics throughout storage and retrieval. The memory is low noise, high speed and broadly tunable; it therefore promises to be a versatile light-matter interface for local quantum processing applications.

DOI: 10.1103/physrevlett.114.053602

Related papers

Storage of polarization-entangled THz-bandwidth photons in a diamond quantum memory

Kent Bonsma-Fisher, Duncan G. England, Jean-Philippe W. MacLean +4 more

Bulk diamond phonons have been shown to be a versatile platform for the generation, storage, and manipulation of high-bandwidth quantum states of light. Here we demonstrate a diamond quantum memory that stores, and releases on demand, an arbitrarily polarized $\ensuremath{\sim}250$ fs duration photonic qubit. The single-mode nature of the memory is overcome by mapping the two degrees of polarization of the qubit, via Raman transitions, onto two spatially distinct optical phonon modes located in the same diamond crystal. The two modes are coherently recombined upon retrieval and quantum process tomography confirms that the memory faithfully reproduces the input state with average fidelity $0.784\ifmmode\pm\else\textpm\fi{}0.004$ with a total memory efficiency of $(0.76\ifmmode\pm\else\textpm\fi{}0.03)%$. In an additional demonstration, one photon of a polarization-entangled pair is stored in the memory. We report that entanglement persists in the retrieved state for up to 1.3 ps of storage time. These results demonstrate that the diamond phonon platform can be used in concert with polarization qubits, a key requirement for polarization-encoded photonic processing.

arXiv:1706.05978Physical Review AJul 18, 201723 citations

Photons & Phonons: A room-temperature diamond quantum memory

Kent Bonsma-Fisher

This thesis presents demonstrations of the storage and manipulation of single photons in \na room-temperature diamond quantum memory using a Raman memory protocol. We \nreport on results from four experiments. \n \nIn the first we demonstrate single photon storage and, upon retrieval, verify the quantum \nnature of the light with a Hanbury Brown Twiss measurement of g^(2)(0) = 0.65±0.07. \nA measurement of g^(2)(0) < 1 is indicative of quantum light. This is the first demonstration \nof single photon storage where the bandwidth of the stored light is greater than 1 THz. The \ndiamond memory stores light for over 13 times the duration of the input wavepacket. In \nthe second experiment, we report the storage and retrieval of polarization-encoded qubits \nand demonstrate qubit storage above a classical bound. We also verify that entanglement \nbetween the input photon and an auxiliary persists through storage and retrieval. \nWe then turn to additional uses of a Raman quantum memory. We demonstrate that \na photon stored in the diamond memory can, upon retrieval, have its frequency and bandwidth \nconverted. We report frequency conversion over a range of 4.2 times the bandwidth of \nthe input photon (4.1 nm, 2.3 THz), and bandwidth modulation between 0.5 to 1.9 times \nthe bandwidth of the input. We verify that the output light from storage and spectral \nmanipulation is still non-classical in nature. \n \nFinally, we demonstrate both single- and two-photon quantum interference mediated \nby the diamond memory, where the memory acts as a beamsplitter between photon and \noptical phonon modes in the diamond lattice. In a first experiment, a single photon is split \ninto two time-bins. The first time-bin is stored in the memory, then recalled and made to \ninterfere with the second time-bin producing fringes. In a second experiment, a photon \nfrom a weak coherent state is stored in the memory and, upon retrieval, undergoes Hong- \nOu-Mandel interference with a second photon. We measure Hong-Ou-Mandel interference \nwith a visibility of 59% giving a signature of non-classical interference (> 50%). \nThis collection of experiments establishes the diamond memory as a prime candidate for \ncertain quantum communication and processing applications. These results demonstrate \nthe potential for the diamond memory to be an integrated platform for photon storage, \nspectral conversion, and information processing.

Aug 19, 20161 citation

A THz-Bandwidth Optical Memory for Quantum Storage

Duncan G. England, Philip J. Bustard, Benjamin Sussman

We have demonstrated a THz-bandwidth quantum memory using the optical phonon modes of room-temperature diamond [1]. A noise-floor of just 0.007 photons per pulse provides the opportunity to store photons produced by spontaneous parametric downconversion.

Jan 1, 20140 citations

Storage and retrieval of ultrafast single photons using a room-temperature diamond quantum memory

Kent Bonsma-Fisher, Duncan G. England, Jean-Philippe W. MacLean +4 more

We experimentally demonstrated the storage and retrieval of THz-bandwidth single photons in a room-temperature diamond quantum memory. We have shown that the non-classical nature of retrieved light is preserved by the memory process.

Jan 1, 20152 citations

Frequency and bandwidth conversion of single photons in a room-temperature diamond quantum memory

Kent Bonsma-Fisher, Duncan G. England, Jean-Philippe W. MacLean +3 more

The spectral manipulation of photons is essential for linking components in a quantum network. Large frequency shifts are needed for conversion between optical and telecommunication frequencies, while smaller shifts are useful for frequency-multiplexing quantum systems, in the same way that wavelength division multiplexing is used in classical communications. Here we demonstrate frequency and bandwidth conversion of single photons in a room-temperature diamond quantum memory. Heralded 723.5 nm photons, with 4.1 nm bandwidth, are stored as optical phonons in the diamond via a Raman transition. Upon retrieval from the diamond memory, the spectral shape of the photons is determined by a tunable read pulse through the reverse Raman transition. We report central frequency tunability over 4.2 times the input bandwidth, and bandwidth modulation between 0.5 and 1.9 times the input bandwidth. Our results demonstrate the potential for diamond, and Raman memories in general, as an integrated platform for photon storage and spectral conversion.

arXiv:1509.05098Nature CommunicationsApr 5, 201665 citations

Room temperature caesium quantum memory for quantum information applications

Patrick Michelberger

Quantum memories are key components in quantum information networks. Their ability to store and retrieve information on demand makes repeat-until-success strategies scalable. Warm alkali-metal vapours are interesting candidates for the implementation of such memories, thanks to their long storage times and experimental simplicity. Operation with the Raman protocol enables high time-bandwidth products, which allows for multiple synchronisation trials of probabilistically operating quantum gates via memory-based temporal multiplexing. This makes the Raman memory a promising tool, whose broad spectral bandwidth facilitates direct interfacing with other photonic primitives, such as single photon sources. Here, such a light-matter interface is implemented in a warm caesium vapour. Firstly, we study the storage of polarisation-encoded information in the memory. High quality polarisation preservation for bright coherent state input signals can be achieved, when operating the Raman memory in a dual-rail configuration inside a polarisation interferometer. Secondly, heralded single photons are stored in the memory. To this end, the memory is operated on-demand by feed-forward of source heralding events, which is a key technological capability. Prior to storage, single photons are produced in a spontaneous parametric down conversion source, whose bespoke design spectrally tailors the photons to the memory acceptance line. The faithful retrieval of stored single photons is found to be currently limited by noise in the memory, with a signal-to-noise ratio of 0.3 in the memory output. Nevertheless, a clear influence of the input's quantum nature is observed in the retrieved light by measuring signal's photon statistics. Finally, the memory noise processes are examined in detail. Four-wave-mixing noise is determined as the sole important noise source for the Raman memory.

arXiv:1706.01104Jan 1, 20150 citations