The reduction of surface plasmon losses in quasi-suspended graphene.

Alexander M Dubrovkin,Nikolay I Zheludev,Qi Jie Wang,Xue Chao Yu,Jin Tao

doi:10.1038/srep09837

Alexander M Dubrovkin, Nikolay I Zheludev + Show 3 more

Open Access

https://doi.org/10.1038/srep09837

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Abstract

Highly confined surface plasmons on graphene attract substantial interest as potential information carriers for highly integrated photonic data processing circuits. However, plasmon losses remain the main obstacle for implementation of such devices. In near-field microscopic experiments performed at the wavelength of 10 μm we show that a substantial reduction of plasmon damping can be achieved by placing a nanometric polymer nano-dots spacer between the graphene layer and the supporting silicon oxide slab making graphene quasi-suspended. We argue that reduction of plasmon losses is attributed to weaker coupling with substrate phonons in the quasi-suspended graphene.

Highlights

Confined surface plasmons on graphene attract substantial interest as potential information carriers for highly integrated photonic data processing circuits
Mid-infrared graphene plasmons (GPs) have attracted tremendous interest in recent years owing to an unprecedented spatial confinement and tunability by electrostatic gating[1,2,3,4,5,6,7,8,9] which are the key features for building the generation photonic and optoelectronic devices[10,11,12,13]
Further experimental study of GPs damping mechanisms and approaches to increase the propagating distance are highly important for the development of future on-chip mid-infrared plasmonic devices[13,21,25,26,27]

Summary

Results and Discussion

To experimentally image GPs, we use scanning plasmon interferometry technique[24,42] which was used in the pioneering works revealing the mid-infrared propagating plasmons in graphene[1,2]. We suggest that the estimated ∆ is related to the half wavelength (λgp/2) of propagating GPs reflected from the dot This data shows an increase of this parameter by about 4-5 times for all calculated NS geometries, compared to graphene on bare SiO2, that represents a significant suppression of damping and agrees with the experiment. This work contributes to understanding of mid-infrared GPs damping mechanism, and gives insight into the fundamental problems of interaction of the plasmons with deeply subwavelength nanostructures

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