Broadband single-photon-level memory in a hollow-core photonic crystal fibre

Abstract

Storing information encoded in light is critical for realizing optical buffers for all-optical signal processing(1,2) and quantum memories for quantum information processing(3,4). These proposals require efficient interaction between atoms and a well-defined optical mode. Photonic crystal fibres can enhance light-matter interactions and have engendered a broad range of nonlinear effects(5); however, the storage of light has proven elusive. Here, we report the first demonstration of an optical memory in a hollow-core photonic crystal fibre. We store gigahertz-bandwidth light in the hyperfine coherence of caesium atoms at room temperature using a far-detuned Raman interaction. We demonstrate a signal-to-noise ratio of 2.6:1 at the single-photon level and a memory efficiency of 27 +/- 1%. Our results demonstrate the potential of a room-temperature fibre-integrated optical memory for implementing local nodes of quantum information networks

Optical Nanofibers

“…In fact, there is an active area of research studying waveguides constructed via nanofabrication techniques, whose mode produces a large OD for a single atom Thompson et al (2013); Goban et al (2014Goban et al ( , 2015; Hood et al (2016). Important advances have happened, for example, with hollow-core fibers: encasing an atomic vapor into the hollow core of a photonic-crystal fiber to confine atoms and photons in the waveguide increases C, but the manipulation of the atoms is not as straightforward as if they are outside the photonic structure as in Ghosh et al (2006); Bajcsy et al (2009);Venkataraman et al (2011); Sprague et al (2014). Optical nanofibers (ONFs) formed by thinning single-mode optical fibers to sub-wavelength diameters, as shown in Fig.…”

Mesoscale cavities in hollow-core waveguides for quantum optics with atomic ensembles

“…Several notable demonstrations of strong light-matter interactions in hollow-core waveguides have been reported in recent years, such as all-optical switching with a few-hundred photons in a hollow-core photonic crystal fiber with laser-cooled atoms [3], cross-phase modulation with few photons [4], and single-photon broadband quantum memory [5] in a photonic-crystal fiber filled with room-temperature alkali atoms, as well as demonstration of quantum state control of warm alkali vapor in a hollow-core antiresonant reflection optical waveguide on a chip [6]. These light-matter interactions could, however, be further enhanced through additional control over the design of the photonic environment of the waveguide and by including additional functionalities.…”

A Cavity-Enhanced Room-Temperature Broadband Raman Memory

“…We solve this problem by introducing a new cavity enhanced Raman memory protocol. We place the atoms inside a low-finesse optical cavity that both enhances the strength of the Raman interaction, reducing the power requirements on the control field, and also suppresses four-wave mixing.To describe how the cavity enhances the memory, we first introduce the standard Raman protocol, which we have developed in caesium vapour at ∼ 70• C [8,17,[25][26][27], using the Λ-system of the Cs D2 line comprising the hyperfine ground states 6S 1/2 , F = 3 (|3 ), F = 4 (|1 ), with a hyper-fine splitting of ∆ HF = 9.2 GHz and the 6P 3/2 excited state manifold (|2 ), whose hyarXiv:1510.04625v1 [quant-ph] …”

“…• C [8,17,[25][26][27], using the Λ-system of the Cs D2 line comprising the hyperfine ground states 6S 1/2 , F = 3 (|3 ), F = 4 (|1 ), with a hyper-fine splitting of ∆ HF = 9.2 GHz and the 6P 3/2 excited state manifold (|2 ), whose hyarXiv:1510.04625v1 [quant-ph]…”