Plasmons, collective high-frequency oscillations of electron systems, can in theory be used to create compact solid-state devices for on-chip spectroscopy of terahertz (THz) radiation. Despite significant interest and experimental efforts, it has proven challenging to implement such devices. The material that can be used to meet this challenge is graphene as it supports long-lived electrically-tunable plasmons. Here, we demonstrate plasmon-assisted detection of THz radiation by antenna-coupled graphene field effect transistors that act as both rectifying elements and plasmonic Fabry-Perot cavities amplifying the photoresponse. By varying the plasmon velocity with gate voltage, we tune our detectors between different resonant modes and exploit this functionality to measure plasmon wavelength and lifetime. Our work opens a convenient venue for further plasmonic research that is often exceedingly difficult under non-ambient conditions (e.g., at cryogenic temperatures and high magnetic fields). The demonstrated resonant detection also promises a viable route for various THz applications.
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Showing posts with label M. Polini. Show all posts
Showing posts with label M. Polini. Show all posts
Friday, July 20, 2018
Abstract-Resonant Terahertz Detection Using Graphene Plasmons
Wednesday, September 12, 2012
Abstract-Graphene field-effect transistors as room-temperature terahertz detectors
Authors: L. Vicarelli, M. S. Vitiello, D. Coquillat, A. Lombardo, A. C. Ferrari, W. Knap, M. Polini, V. Pellegrini A. Tredicucci
The unique optoelectronic properties of graphene make it an ideal platform for a variety of photonic applications, including fast photodetectors, transparent electrodes in displays and photovoltaic modules, optical modulators, plasmonic devices, microcavities, and ultra-fast lasers. Owing to its high carrier mobility, gapless spectrum and frequency-independent absorption, graphene is a very promising material for the development of detectors and modulators operating in the terahertz region of the electromagnetic spectrum (wavelengths in the hundreds of micrometres), still severely lacking in terms of solid-state devices. Here we demonstrate terahertz detectors based on antenna-coupled graphene field-effect transistors. These exploit the nonlinear response to the oscillating radiation field at the gate electrode, with contributions of thermoelectric and photoconductive origin. We demonstrate room temperature operation at 0.3 THz, showing that our devices can already be used in realistic settings, enabling large-area, fast imaging of macroscopic samples.
Nature Materials. doi:10.1038/nmat3417
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