Navajas David, Pérez-Escudero José M, Martínez-Hernández María Elena, Goicoechea Javier, Liberal Iñigo
Department of Electrical, Electronic and Communications Engineering, Institute of Smart Cities (ISC), Public University of Navarre (UPNA), 31006 Pamplona, Spain.
ACS Photonics. 2023 Aug 22;10(9):3105-3114. doi: 10.1021/acsphotonics.3c00476. eCollection 2023 Sep 20.
Epsilon-near-zero (ENZ) media have been very actively investigated due to their unconventional wave phenomena and strengthened nonlinear response. However, the technological impact of ENZ media will be determined by the quality of realistic ENZ materials, including material loss and surface roughness. Here, we provide a comprehensive experimental study of the impact of surface roughness on ENZ substrates. Using silicon carbide (SiC) substrates with artificially induced roughness, we analyze samples whose roughness ranges from a few to hundreds of nanometer size scales. It is concluded that ENZ substrates with roughness in the few nanometer scale are negatively affected by coupling to longitudinal phonons and strong ENZ fields normal to the surface. On the other hand, when the roughness is in the hundreds of nanometers scale, the ENZ band is found to be more robust than dielectric and surface phonon polariton (SPhP) bands.
由于其非常规的波动现象和增强的非线性响应，近零介电常数（ENZ）介质受到了非常积极的研究。然而，ENZ介质的技术影响将取决于实际ENZ材料的质量，包括材料损耗和表面粗糙度。在此，我们提供了一项关于表面粗糙度对ENZ衬底影响的全面实验研究。使用具有人工诱导粗糙度的碳化硅（SiC）衬底，我们分析了粗糙度范围从几纳米到数百纳米尺寸尺度的样品。得出的结论是，粗糙度在几纳米尺度的ENZ衬底会因与纵向声子耦合以及垂直于表面的强ENZ场而受到负面影响。另一方面，当粗糙度处于数百纳米尺度时，发现ENZ带比介电和表面声子极化激元（SPhP）带更稳健。
