Coherent terahertz radiation from a nonlinear oscillator of viscous electrons

Christian B. Mendl, Marco Polini, Andrew Lucas

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Compressible electron flow through a narrow cavity is theoretically unstable, and the oscillations occurring during the instability have been proposed as a method of generating terahertz radiation. We numerically demonstrate that the end point of this instability is a nonlinear hydrodynamic oscillator, consisting of an alternating shock wave and rarefaction-like relaxation flowing back and forth in the device. This qualitative physics is robust to cavity inhomogeneity and changes in the equation of state of the fluid. We discuss the frequency and amplitude dependence of the emitted radiation on physical parameters (viscosity, momentum relaxation rate, and bias current) beyond linear response theory, providing clear predictions for future experiments.

Original languageEnglish
Article number013105
JournalApplied Physics Letters
Issue number1
StatePublished - 4 Jan 2021


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