From the Thermal Radiation of Sub-Lambda Resonators to the Electroluminescence of Graphene

Modulation spectroscopy enables the investigation of weak infrared radiation signals produced by sources with size is in the micrometer range. We have used this method first to investigate the thermal radiation from single subwavelength sized metallic or dielectric resonators. Next, we have adapted our setup to investigate the radiation from transistors made of graphene microstructures encapsulated in boron nitride (hBN). It is shown that the infrared emission from these devices exhibits features which are typical for electroluminescence and is concomitant with the occurrence of Zener Klein tunneling.