Efficient Coupling of Atoms to Nanophotonic waveguide with NO Nanofabrication – E-CANNON

Waveguide Quantum Electrodynamics (WQED) studies the interaction between multiple quantum emitters and a guided electromagnetic (EM) mode. This domain is foreseen as key for quantum technology development and has been flourishing with theoretical proposals ranging from quantum information protocols, generation of non-classical state of light and quantum simulation. The performances of experimental platforms are mainly assessed by their ability to sustain N vacuum-limited quantum emitters coupled to a single EM mode. In practice, this is obtained by transversally suppressing and longitudinally enhancing the EM density of states. This engineering of the EM coupling is usually done by placing the emitters inside or close to a nanofabricated waveguide. For optical wavelengths, this engineering is extremely sensitive to any residual defect, even at the nanometer scale. Such sensitivity has for now limited the achievable performance with nanofabricated waveguides.

The E-CANNON project proposes a paradigmatic shift by using a structured cold atom ensemble to both tailor the EM modes and provide quantum emitters naturally embedded in the guided mode. Guiding down to a single transverse mode will be achieved using a cigar-shaped ultracold quantum gas, while a 1D modulation of the refractive index will create a band gap with an enhanced density of state at the band edges. Simultaneously, using optical dressing engineering, several independent two-level emitters can be isolated and made to emit directly in the guide. This project leverages on innovative and potentially very efficient solutions to control the scattering properties of cold atom ensemble. We propose to characterize these solutions on two complementary experimental platforms: a dilute cold atom gas trapped in a 1D lattice at INPHYNI (Nice) and a cigar-shaped ultra-cold quantum gas with structured coherence at LP2N (Bordeaux).

Our goal within E-CANNON is to demonstrate the performance of the proposed solutions: close to unity single atom radiative coupling to the guided mode and the capability to accommodate many quantum emitters. If successful, this new platform would be ideal to efficiently implement WQED protocols.