Aupiais Ian, Grasset Romain, Guo Tingwen, Daineka Dmitri, Briatico Javier, Houver Sarah, Perfetti Luca, Hugonin Jean-Paul, Greffet Jean-Jacques, Laplace Yannis
LSI, CEA/DRF/IRAMIS, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France.
LPICM, CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, Palaiseau, France.
Nat Commun. 2023 Nov 23;14(1):7645. doi: 10.1038/s41467-023-43394-w.
The ability to confine THz photons inside deep-subwavelength cavities promises a transformative impact for THz light engineering with metamaterials and for realizing ultrastrong light-matter coupling at the single emitter level. To that end, the most successful approach taken so far has relied on cavity architectures based on metals, for their ability to constrain the spread of electromagnetic fields and tailor geometrically their resonant behavior. Here, we experimentally demonstrate a comparatively high level of confinement by exploiting a plasmonic mechanism based on localized THz surface plasmon modes in bulk semiconductors. We achieve plasmonic confinement at around 1 THz into record breaking small footprint THz cavities exhibiting mode volumes as low as [Formula: see text], excellent coupling efficiencies and a large frequency tunability with temperature. Notably, we find that plasmonic-based THz cavities can operate until the emergence of electromagnetic nonlocality and Landau damping, which together constitute a fundamental limit to plasmonic confinement. This work discloses nonlocal plasmonic phenomena at unprecedentedly low frequencies and large spatial scales and opens the door to novel types of ultrastrong light-matter interaction experiments thanks to the plasmonic tunability.
将太赫兹光子限制在深亚波长腔内的能力，有望对基于超材料的太赫兹光工程以及在单发射器水平上实现超强光与物质耦合产生变革性影响。为此，迄今为止最成功的方法依赖于基于金属的腔结构，因为它们能够限制电磁场的传播并从几何上调整其共振行为。在此，我们通过利用基于体半导体中局域太赫兹表面等离子体模式的等离子体机制，通过实验证明了相对较高的限制水平。我们在约1太赫兹频率下实现了等离子体限制，进入了创纪录的小尺寸太赫兹腔，其模式体积低至[公式：见原文]，具有出色的耦合效率以及随温度的大频率可调性。值得注意的是，我们发现基于等离子体的太赫兹腔可以运行到电磁非局域性和朗道阻尼出现，这两者共同构成了等离子体限制的基本极限。这项工作在前所未有的低频和大空间尺度上揭示了非局域等离子体现象，并由于等离子体可调性为新型超强光与物质相互作用实验打开了大门。
