Corrugated graphene for synchrotron-like coherent THz emission

The use of geometrical constraints to induce synchrotron-like radiations represents an original concept for light emission in condensed matter [1] - [3] . Here, we show that corrugated graphene is a good candidate as a new type of room temperature compact THz emitters based on synchrotron approach. We perform electrodynamic calculation with a model of charges in periodic angular motion and study the radiation properties such as output power and spectral decomposition. We demonstrate that technologically significant output power levels can be obtained as well as geometrically tunable THz frequencies ( Fig. 1. a )). We further report on the first technological fabrication of corrugated hBN-encapsulated graphene devices for synchrotron-like THz emission ( Fig. 1. b) and c) ). We characterize such a device with low-bias transport measurements at 4 K and Raman measurements ( Fig 1. d) ) and show interesting deviation from behaviour of plane graphene [4] , [5] . The drain-source resistance, R ds , is highly V ds- dependent, the charge neutrality area forms a plateau and we observe shoulders on both sides of this plateau. These unique tendencies are assumed to be due to the non-uniform doping in the corrugated graphene layer created by the backgate [4] , [5] . The Raman characterization of the device shows a clear signature of the presence of corrugations. Moreover by performing a spatial deconvolution of the Raman spectra on the corrugation, we obtain periodically a splitting of the 2D peak which is typical of the presence of stress in the graphene sheet [6] . The graphene is under a periodic stress which can be seen as a hamiltonian perturbation equivalent to a periodic pseudo-B field applied to the graphene.