Spontaneous Scattering of Raman Photons from Cavity-QED Systems in the Ultrastrong Coupling Regime

TL;DR

This paper demonstrates that spontaneous Raman scattering can occur in cavity-QED systems within the ultrastrong coupling regime, providing a new method for system characterization and quantum state generation without external vibrational coupling.

Contribution

It introduces the observation of Raman scattering in cavity-QED systems driven by ultrastrong coupling, supported by a quantum mechanical framework.

Findings

Raman resonances appear in emission spectra near ultrastrong coupling

Ultrastrong coupling is essential for observing Raman scattering

The effect is highly sensitive to system parameters

Abstract

We show that spontaneous Raman scattering of incident radiation can be observed in cavity-QED systems without external enhancement or coupling to any vibrational degree of freedom. Raman scattering processes can be evidenced as resonances in the emission spectrum, which become clearly visible as the cavity-QED system approaches the ultrastrong coupling regime. We provide a quantum mechanical description of the effect, and show that ultrastrong light-matter coupling is a necessary condition for the observation of Raman scattering. This effect, and its strong sensitivity to the system parameters, opens new avenues for the characterization of cavity QED setups and the generation of quantum states of light.