Bidimensional nanomaterials to propagate light at nanoscale
International research undertaken by researchers from ICFO and CIC nanoGUNE, amongst other centres, has enabled compressing light into small devices and controlling their flow of electricity, thanks to the union of graphene (a layer of carbon atoms) and boron nitride (a good bidimensional insulator). Such a promising bidimensional accomplishment has been made possible through taking advantage of what are known as plasmons: quasiparticles in which electrons and light move together as a coherent wave.
The plasmons, guided by the graphene, can be limited to nanometric wave scales, up to 200 times smaller than the wavelength of light. An important obstacle to date, however, has been the rapid loss of energy that these plasmons undergo, thus limiting the range within which they can travel. This problem has been solved thanks to the union between graphene and boron nitride. The combination of these two unique bidimensional materials has provided the solution to controlling light in small devices, as well as obviating energy losses. When the graphene is encapsulated within boron nitride, the electrons can travel, ballistically, large distances without dispersion, including at ambient temperature. This research shows that the graphene/boron material nitride system is also an excellent host to extremely strongly confined light as well as to suppressing loss of plasmons.
The research was carried out by researchers from ICFO (Barcelona), nanoGUNE and CNR/Scuola Normale Superiore (Pisa) — all members of the EU Graphene Flagship, and the US universities of Columbia and Missouri.
According to Ikerbasque researcher Rainer Hillenbrand, Nano-optics team leader at nanoGUNE, “we are now able to compress light and, at the same time, propagate it for considerable distances by employing nanomaterials. In the future, thanks to the fact that plasmon loss is insignificant, much faster signal processing and information processing can be achieved, with greater optical sensitivity”.
According to the authors of the research, this is only the beginning of a series of discoveries about the nano-optoelectronic properties of this new heterostructure, previously discovered at the University of Columbia.
These discoveries open the path to extremely miniaturised optical circuits and devices which can be useful for biological detection, information processing and data communication.