Centre for Disruptive Photonic Technologies, TPI, SPMS, Nanyang Technological University, 637371, Singapore, Singapore.
Optoelectronics Research Centre and Centre for Photonic Metamaterials, University of Southampton, Southampton, SO17 1BJ, UK.
Nat Commun. 2018 May 2;9(1):1762. doi: 10.1038/s41467-018-04168-x.
Improvements in device density in photonic circuits can only be achieved with interconnects exploiting highly confined states of light. Recently this has brought interest to highly confined plasmon and phonon polaritons. While plasmonic structures have been extensively studied, the ultimate limits of phonon polariton squeezing, in particular enabling the confinement (the ratio between the excitation and polariton wavelengths) exceeding 10, is yet to be explored. Here, exploiting unique structure of 2D materials, we report for the first time that atomically thin van der Waals dielectrics (e.g., transition-metal dichalcogenides) on silicon carbide substrate demonstrate experimentally record-breaking propagating phonon polaritons confinement resulting in 190-times squeezed surface waves. The strongly dispersive confinement can be potentially tuned to greater than 10 near the phonon resonance of the substrate, and it scales with number of van der Waals layers. We argue that our findings are a substantial step towards infrared ultra-compact phonon polaritonic circuits and resonators, and would stimulate further investigations on nanophotonics in non-plasmonic atomically thin interface platforms.
在光子电路中提高器件密度只能通过利用高度限制的光状态的互连来实现。最近，这引起了对高度限制的等离子体激元和声子极化激元的兴趣。虽然已经广泛研究了等离子体结构，但声子极化激元压缩的极限，特别是能够实现超过 10 的限制（激发和极化激元波长之比），仍有待探索。在这里，我们利用二维材料的独特结构，首次报告称，碳化硅衬底上的原子层状范德华电介质（例如过渡金属二卤化物）在实验中展示了创纪录的传播声子极化激元限制，从而产生了 190 倍压缩的表面波。在接近衬底声子共振的情况下，强烈色散限制可以潜在地调谐到大于 10，并且它与范德华层的数量成正比。我们认为，我们的发现是朝着红外超紧凑声子极化激元电路和谐振器迈出的重要一步，并将激发对非等离子体原子层状界面平台中的纳米光子学的进一步研究。
