Liu Zizhuo, Aydin Koray
Opt Express. 2016 Nov 28;24(24):27882-27889. doi: 10.1364/OE.24.027882.
Graphene is a monolayer plasmonic material that has been widely studied in the area of plasmonics and nanophotonics. Combining graphene with traditional plasmonic structures provides new opportunities and challenges. One particular application for nanostructured metals is enhanced optical transmission. However, extraordinary transmission (EOT) is known to have a frequency-selective performance due to size and periodicity of the nanohole arrays. Here, we propose to use a continuous graphene layer to enhance transmission through gold nanoslit arrays at mid-infrared (mid-IR) wavelengths. Although graphene absorbs 2.3% of light, by exciting surface plasmon polaritons (SPPs) at the graphene/gold nanoslit arrays interface, we have theoretically demonstrated enhanced infrared transmission over broad range of wavelengths in the mid-IR region. Our analyses of the effects of various structure parameters on the transmittance spectra shows that surface plasmon polaritons excited at the graphene/metal interface is responsible for enhanced transmission behavior. Moreover, calculated steady-state electric field distribution supports our predictions. Our work opens new directions to study 2D plasmonics using a continuous graphene film without the need of structuring it and also employs the broadband optical response of graphene to enable broadband extraordinary transmission enhancement.
石墨烯是一种单层等离子体材料，已在等离子体学和纳米光子学领域得到广泛研究。将石墨烯与传统等离子体结构相结合带来了新的机遇和挑战。纳米结构金属的一个特殊应用是增强光传输。然而，由于纳米孔阵列的尺寸和周期性，超常透射（EOT）具有频率选择性性能。在此，我们提出使用连续的石墨烯层来增强中红外（mid-IR）波长下通过金纳米狭缝阵列的传输。尽管石墨烯吸收2.3%的光，但通过在石墨烯/金纳米狭缝阵列界面激发表面等离激元极化激元（SPPs），我们在理论上证明了在中红外区域的宽波长范围内红外传输得到增强。我们对各种结构参数对透射光谱影响的分析表明，在石墨烯/金属界面激发的表面等离激元极化激元是增强传输行为的原因。此外，计算得到的稳态电场分布支持了我们的预测。我们的工作为研究二维等离子体学开辟了新方向，即使用连续的石墨烯薄膜而无需对其进行结构化处理，并且利用石墨烯的宽带光学响应来实现宽带超常传输增强。
