séminaire LPEM - Y. Todorov

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8 février 13:50 » 15:30 — Charpak

Ultra-strong light-matter coupling regime in semiconductor devices

by Y. Todorov, Laboratoire de Physique de l’Ecole normale supérieure, ENS-PSL
The regime of ultra-strong light matter coupling (USC) was introduced by Ciuti et al. in 2005 [1] and has been attracting considerable interest ever since. This regime appears when a single material excitation interacts resonantly with a single microcavity mode, such as the coupling constant becomes of the same order of magnitude as the matter excitation frequency. In such systems where light-matter interaction is highly non-perturbative, electromagnetic vacuum fluctuations can lead to altering of the fundamental properties of materials such as electrical conductivity, rate of chemical reactions, topological order, and non-linear susceptibility. I will talk about our past experimental and theoretical investigation of ultra-strongly coupled systems based on highly doped semiconductor quantum wells [2]. In that case, collective electronic resonances dominate the interaction with light, and the systems is conveniently described in the Power-Zienau-Wooley representation of quantum electrodynamics [3]. I will also present recent results where USC is explored in a quantum cascade detector operating in the 9 µm wavelength range [4].
1. Ciuti, C., Bastard, G. & Carusotto, I. Quantum vacuum properties of the intersubband cavity polariton field. Physical Review B 72, 115303 (2005).
2. Todorov, Y. et al. Ultrastrong light-matter coupling regime with polariton dots. Physical review letters 105, 196402 (2010).
3. Claude Cohen‐Tannoudji ; Jacques Dupont‐Roc ; Gilbert Grynberg, “Photons & Atoms : Introduction to Quantum Electrodynamics”, CNRS ed. 1987
4. Pisani, F. et al. “Electronic transport driven by collective light-matter coupled states in a quantum device”, Nat Commun, 14, 3914 (2023).




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