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arXiv 2405.15420physics.opticscond-mat.mes-hall
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可见光频率下天然范德华晶体中的双曲等离激元极化激元

Visible-frequency hyperbolic plasmon polaritons in a natural van der Waals crystal

Giacomo Venturi, Andrea Mancini, Nicola Melchioni, Stefano Chiodini, Antonio Ambrosio

AI总结:

本研究在天然范德华晶体MoOCl2中实验证实了可见及近红外波段低损耗面内双曲等离激元极化激元,为超透镜、超分辨成像等应用提供新平台。

摘要:

在亚波长尺度上控制光是纳米光子学的主要挑战之一。利用支持任意大波矢的双曲极化激元可以实现极度的光场局域,有效克服衍射极限。双曲性最初在人工超材料中实现,但其性能受到金属组分高损耗的限制。虽然最近发现的天然低损耗双曲声子极化激元重新引发了人们对双曲材料的兴趣,但它们局限于中红外频率范围,限制了其在多种应用中的使用。一些可见光频率下的双曲材料已被研究,但它们要么损耗很高,要么仅具有面外双曲性。在此,我们证明了在天然范德华晶体MoOCl2薄膜中,可见光和近红外波段存在低损耗、面内双曲等离激元极化激元。极化激元色散基于双轴介质中光传播的框架进行预测,并通过在剥离薄片上的实空间纳米成像得到实验证实。MoOCl2构成了一个新型材料平台,可利用双曲模式的无界性实现可见光范围的应用,如超透镜、Purcell因子增强和超分辨成像,而无需超材料的缺点。

英文摘要:

Controlling light at subwavelength scales is one of the main challenges of nanophotonics. Leveraging hyperbolic polaritons supporting arbitrarily large wavevectors can lead to extreme light confinement, effectively overcoming the diffraction limit. Hyperbolicity was initially realized in artificial metamaterials, but their performances are limited by high losses in the metallic components. While recently discovered natural low-loss hyperbolic phonon polaritons initiated a revival in the interest for hyperbolic materials, they are confined to the mid-infrared frequency range, limiting their use for several applications. Some hyperbolic materials at visible frequencies have been studied, but they are either very lossy or only feature out-of-plane hyperbolicity. Here, we demonstrate the presence of low-loss, in-plane hyperbolic plasmon polaritons in the visible and near-infrared in thin films of $\mathrm{MoOCl}_2$, a natural van der Waals crystal. The polariton dispersion is predicted based on the framework of light propagation in biaxial media, and experimentally confirmed by real space nano imaging on exfoliated flakes. $\mathrm{MoOCl}_2$ constitutes a novel material platform for visible-range applications leveraging the unboundedness of hyperbolic modes, such as hyperlensing, Purcell factor enhancement and super-resolution imaging, without the drawbacks of metamaterials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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