02 May 2016 ICFO in the April cover of Nature Photonics

A study by CIC nanoGUNE, ICFO and Graphenea on graphene plasmonics makes it to the cover of Nature Photonics. In continuous quest for miniaturizing commercial devices, integrated micro-optical elements play a central role in the development of applications where graphene plasmons may offer a compelling platform for photonic technologies. Graphene plasmons enable extremely strong concentration of light, and possess intriguing properties such as electro-optical tunability and relatively high quality factors.

Enhanced plasmons in graphene nanostructures, which act as nanoresonators, have many potential applications in photonics and optoelectronics, including room temperature infrared and terahertz photodetectors, sensors, reflect arrays, modulators, or even infrared vibrational sensing of molecules, among others.

Until now localized plasmonic modes in graphene nanostructures have mainly been analysed experimentally by far-field spectroscopy. However, this technique proved incapable of providing a comprehensive experimental characterization of graphene plasmonic nanoresonators. These nanoresonators vibrate in two modes: sheet and edge modes, the former existing inside graphene nanostructures, extending over the whole area of graphene and the latter propagating only along the edges of the graphene nanostructures.

In a recent study, chosen for the April cover of Nature Photonics, researchers from CIC nanoGUNE, ICFO and Graphenea have imaged and analyzed the near-field structure of both plasmonic sheet and edge modes in graphene disks and rectangular nanoresonators. The team of researchers has been able to overcome the current characterization limitations with the use of near-field microscopy to excite and image plasmons in tailored disk and rectangular graphene nanoresonators, and observe a rich variety of coexisting Fabry–Perot modes, disentangling them with the help of theoretical 3D simulations and analysing the resulting data to identify the sheet and edge plasmons.

The work opens new opportunities for ultra-small and efficient photodetectors, sensors and other photonic and optoelectronic nanodevices.