Observation of Superradiant Bursts in a Cascaded Quantum System

Abstract

We experimentally investigate the collective radiative decay of a fully inverted ensemble of two-level atoms for a chiral, i.e., propagation direction-dependent light-matter coupling. Despite a fundamentally different interaction Hamiltonian which has a reduced symmetry compared to the standard Dicke case of superradiance, we do observe a superradiant burst of light. The burst occurs above a threshold number of atoms, and its peak power scales faster with the number of atoms than in the case of free-space Dicke superradiance. We measure the first-order coherence of the burst and experimentally distinguish two regimes, one dominated by the coherence induced during the excitation process and the other governed by vacuum fluctuations. Our results shed light on the collective radiative dynamics of cascaded quantum many-body systems, i.e., systems in which each quantum emitter is only driven by light radiated by emitters that are upstream in the cascade. Our findings may turn out useful for generating multiphoton Fock states as a resource for quantum technologies. Published by the American Physical Society 2024

Atom-light interactions using optical nanofibres—a perspective

“…This system consists of a few thousand trapped 133 Cs atoms localised in a one-dimensional lattice, exhibiting long atomic coherence times and high optical depth [113]. It is well-suited for investigating a range of interesting quantum phenomena [114][115][116][117][118][119], particularly an experimental exploration of collective atom-light interactions mediated by the ONF [120][121][122][123], development of novel quantum light sources [124,125], and for creating collective states resulting from atom-atom interactions through the nanofibre [126]. These phenomena hold great potential for applications in quantum information processing and quantum many-body physics [41,58,127].…”