Spectra of two-dimensional “proximity” plasmons measured by the standing-wave method

Plasma excitations in a two-dimensional electron system partially screened by a metal strip gate are investigated using the optical detection of resonance microwave absorption. The optimal geometric parameters of the structure for the observation of standing waves corresponding to “proximity” plasmons along the strip are found. Four standing modes of proximity plasma waves are detected. The spectrum of proximity plasma excitations is determined by identifying the wave vectors corresponding to each of the modes. The measured spectrum coincides with a high accuracy with the theoretical one.