▎ 摘　　要

The manuscript presents a simple graphene-based device able to generate at room temperature ultrashort pulses in the sub-picosecond range and thus able to generate signals up to 3-4 THz and beyond. The electrons produced by a short laser pulse incident on a graphene monolayer excite two oblique gates polarized with different dc voltages. The two gates are biased such that the quantum transmission has an isolated sharp peak in a narrow energy bandwidth. Such a transmission mimics the main property of a resonant tunneling structure, usually consisting of a semiconductor heterostructure, and generates an electric pulse with sub-picosecond duration and a spectrum with a cutoff frequency that can exceed 3 THz. (C) 2011 American Institute of Physics. [doi:10.1063/1.3594716]