Electromagnetically induced transparency with single atoms in a cavity

TL;DR

This paper demonstrates electromagnetically induced transparency (EIT) with a single atom in a high-finesse cavity, showing potential for quantum information processing and control of light at the quantum level.

Contribution

The work achieves EIT with a single atom in a cavity and explores scaling effects, advancing quantum control of light-matter interactions.

Findings

Successful demonstration of EIT with a single atom in a cavity

Excellent agreement between measured spectra and theoretical models

Potential for quantum optical devices using single-atom cavity QED

Abstract

Optical nonlinearities offer unique possibilities for the control of light with light. A prominent example is electromagnetically induced transparency (EIT) where the transmission of a probe beam through an optically dense medium is manipulated by means of a control beam. Scaling such experiments into the quantum domain with one, or just a few particles of both light and matter will allow for the implementation of quantum computing protocols with atoms and photons or the realisation of strongly interacting photon gases exhibiting quantum phase transitions of light. Reaching these aims is challenging and requires an enhanced matter-light interaction as provided by cavity quantum electrodynamics (QED). Here we demonstrate EIT with a single atom quasi-permanently trapped inside a high-finesse optical cavity. The atom acts as a quantum-optical transistor with the ability to coherently control the transmission of light through the cavity. We furthermore investigate the scaling of EIT when the atom number is increased one by one. The measured spectra are in excellent agreement with a theoretical model. Merging EIT with cavity QED and single quanta of matter is likely to become the cornerstone for novel applications, e.g. the dynamic control of the photon statistics of propagating light fields or the engineering of Fock-state superpositions of flying light pulses.