Floquet engineering of light-matter strong coupling
Phys. Rev. A 112, 043710 – Published 7 October, 2025
DOI: https://doi.org/10.1103/41fc-w2jy
Abstract
Light-matter strong coupling has been the subject of much attention in recent decades, giving optical systems unique features. However, properties of a system with strong coupling are determined by the properties of its components and are thus difficult to control. Here, we propose Floquet engineering, a technique of controlling the energy levels of a quantum system using external fields, as a method of manipulating a hybrid system of a molecule strongly coupled to a single-mode resonator. We show that an external field can change the relative positions of levels in an open strongly coupled system, leading to a change in the rates of transitions between them. We demonstrate that if the frequency of the pumping wave is close to polariton transitions in the hybrid system, nonmonotonic dependence of fluorescence and scattering amplitudes on pump intensity with a narrow resonance-like response occurs. We show that this phenomenon occurs due to hybridization of the lower and upper polaritons with substantially different excitation numbers caused by the pumping affecting polariton states of the system. This occurs when the Rabi interaction with the coherent field is comparable to the field-matter coupling constant, which in turn needs to be sufficient for the manifestation of strong coupling. This nonmonotonic dependence of the fluorescence and scattering amplitudes on pump rate intensity paves the way for the creation of nonlinear optical devices.
