Plasmonic detector/spectrometer of subterahertz radiation based on two-dimensional electron system with embedded defect

We demonstrate that the introduction of a defect in the form of an electron density step into a two-dimensional electron system (2DES) locally rectifies the alternating potential of plasma waves. The rectification mechanism is active at temperatures up to room temperature. We observe photovoltage oscillations in a back-gated 2DES with a density defect, when tuning the density under incident subterahertz radiation. The oscillations originate from the interference of 2D plasma waves excited by subterahertz radiation. The period of oscillations depends on the radiation wavelength. These phenomena can be exploited further to produce detectors/spectrometers for millimeter waves. (C) 2012 American Institute of Physics. [doi:10.1063/1.3688049]