Fast single-photon interface with an atom fiber-cavity system

Introduction:- Cavity-enhanced light-matter interfaces are ubiquitously used in quantum information processing. In this regard, Fiber-based Cavity Quantum Electrodynamics (CQED) platforms are emerging as robust, miniaturized... [ view full abstract ]

Introduction:-

Cavity-enhanced light-matter interfaces are ubiquitously used in quantum information processing. In this regard, Fiber-based Cavity Quantum Electrodynamics (CQED) platforms are emerging as robust, miniaturized modules offering possibilities for scalable and fully fiber integrable systems. Fiber resonators provide simultaneously the small mode volume and high cavity bandwidth enabling both the efficient and fast atom-photon interaction.
We study the strong Purcell effect on an atom coupled to a fiber-cavity and use this interface to store photon pulses in the atomic internal states.

Methods:-
In our experiment we have a strongly coupled atom-cavity system consisting of a single Rb87 neutral atom optically trapped at the center of a fiber Fabry-Perot cavity mode. The unique configuration of four high numerical-aperture lenses, all having their focal plane at the cavity center, provides the necessary optical tools for both the tight 3D optical confinement of the atom in the resonator mode and the ability to efficiently collect their free-space fluorescence.

Results:-
We observe a sixfold Purcell broadening of the D2 line of a Rb87 atom strongly coupled to a single-sided fiber-based Fabry-Perot cavity. The corresponding effect is measured to direct 90% of the emitted photons into the cavity mode for a near-resonant external driving of the atom. The photon leakage through the higher-transmission mirror being the dominant contribution to the field decay (κ ≈ 2π×50 MHz), the system offers a high-bandwidth, fiber-coupled channel for single photon interfaces. The fast atom-cavity regime allows us to store photon pulses below the lifetime of the atomic resonance line.                   
Thus our fiber-based miniaturized cavity QED systems provides a fast and coherent atom-photon interface which is an important prerequisite for the realization of quantum networks.