  Microwave absorption by a high mobility 2DEG has been investigated
experimentally using sensitive Electron Paramagnetic Resonance cavity
technique. It is found that MW absorption spectra are chiefly governed by
confined magnetoplasmon excitations in a 2DEG stripe. Spectra of the 2D
magnetoplasmons are studied as a function of magnetic field, MW frequency and
carrier density. The electron concentration is tuned by illumination and
monitored using optical photoluminescence technique.
