Collectively induced transparency and absorption in waveguide QED with Bragg atom arrays

TL;DR

This paper explores how collective quantum states in waveguide-coupled Bragg atom arrays can induce transparency and absorption effects, revealing new ways to control optical responses in quantum systems.

Contribution

It introduces the concept of collectively induced transparency and absorption in inhomogeneous Bragg atom arrays, demonstrating tunable optical phenomena influenced by atomic frequencies and dissipation.

Findings

Collectively induced transparency results from destructive interference between subradiant and superradiant states.

Tunable atomic frequencies can produce multi-frequency photon transparency and absorption.

Free-space dissipation influences the decay rates of subradiant states and enhances photon absorption at certain frequencies.

Abstract

Collective quantum states, such as subradiant and superradiant states, are useful for controlling optical responses in many-body quantum systems. In this work, we study novel collective quantum phenomena in waveguide-coupled Bragg atom arrays with inhomogeneous frequencies. For atoms without free-space dissipation, collectively induced transparency is produced by destructive quantum interference between subradiant and superradiant states. In a large Bragg atom array, multi-frequency photon transparency can be obtained by considering atoms with different frequencies. Interestingly, we find collectively induced absorption (CIA) by studying the influence of free-space dissipation on photon transport. Tunable atomic frequencies nontrivially modify decay rates of subradiant states. When the decay rate of a subradiant state equals to the free-space dissipation, photon absorption can reach a limit at a certain frequency. In other words, photon absorption is enhanced with low free-space dissipation, distinct from previous photon detection schemes. We also show multi-frequency CIA by properly adjusting atomic frequencies. Our work presents a way to manipulate collective quantum states and exotic optical properties in waveguide QED systems.