近日，德国马克斯·普朗克学会弗里茨·哈伯研究所的Sebastian F. Maehrlein&Michael S. Spencer及其研究团队取得一项新进展。经过不懈努力，他们实现用于腔场原位测量的电光腔。相关研究成果已于2025年2月6日在国际知名学术期刊《光：科学与应用》上发表。

该研究团队提出一种新型主动腔概念，它由电光法布里-珀罗谐振器构成，能够在亚周期时间尺度上测量其腔内电场。据此，研究人员在宽太赫兹（THz）频率范围内，实现了对腔模振幅和相位的定量提取。为了实现腔内采样与激发态材料控制的同步进行，研究人员设计了一种可调谐多层腔，使得能够确定性地设计用于激子-极化子系统的混合腔。

该理论模型理论模型揭示了嵌入在复杂模式色散中的避免交叉的起源，并将在混合腔承载的任意材料中实现完全可切换的极化效应。因此，电光腔（EOCs）将作为所有耦合体系中光-物质相互作用的集成探针，为场分辨腔内量子电动力学奠定基础。

据悉，腔电动力学为定制基态材料特性、激发态工程以及量子物质的灵活控制提供了一条独特途径。将这些概念与太赫兹（THz）光谱范围内的高场物理相结合，为探索由基本共振或序参量引发的低能量、场驱动腔电动力学打开了大门。尽管对此有着迫切需求，但由于无法直接访问腔内场，利用场驱动材料控制在腔中的全部潜力受到了阻碍。

附：英文原文

Title: Electro-optic cavities for in-situ measurement of cavity fields

Author: Spencer, Michael S., Urban, Joanna M., Frenzel, Maximilian, Mueller, Niclas S., Minakova, Olga, Wolf, Martin, Paarmann, Alexander, Maehrlein, Sebastian F.

Issue&Volume: 2025-02-06

Abstract: Cavity electrodynamics offers a unique avenue for tailoring ground-state material properties, excited-state engineering, and versatile control of quantum matter. Merging these concepts with high-field physics in the terahertz (THz) spectral range opens the door to explore low-energy, field-driven cavity electrodynamics, emerging from fundamental resonances or order parameters. Despite this demand, leveraging the full potential of field-driven material control in cavities is hindered by the lack of direct access to the intra-cavity fields. Here, we demonstrate a new concept of active cavities, consisting of electro-optic Fabry-Pérot resonators, which measure their intra-cavity electric fields on sub-cycle timescales. We thereby demonstrate quantitative retrieval of the cavity modes in amplitude and phase, over a broad THz frequency range. To enable simultaneous intra-cavity sampling alongside excited-state material control, we design a tunable multi-layer cavity, enabling deterministic design of hybrid cavities for polaritonic systems. Our theoretical models reveal the origin of the avoided crossings embedded in the intricate mode dispersion, and will enable fully-switchable polaritonic effects within arbitrary materials hosted by the hybrid cavity. Electro-optic cavities (EOCs) will therefore serve as integrated probes of light-matter interactions across all coupling regimes, laying the foundation for field-resolved intra-cavity quantum electrodynamics.

DOI: 10.1038/s41377-024-01685-x

Source: https://www.nature.com/articles/s41377-024-01685-x