Coherent and Incoherent Contributions to the Damping of Cyclotron Magnetoplasma Resonance for Two-Dimensional Electrons

The spectrum of resonant microwave absorption for a two-dimensional electron disk is studied by the optical detection technique. The dependence of the width of cyclotron magnetoplasma resonance on the electron density and on the size of the two-dimensional electron system is analyzed. The contributions of the coherent radiative and incoherent collision mechanisms to the relaxation of magnetoplasma excitations are measured. It is demonstrated that the ratio of the length of the electromagnetic wave and the lateral size of the twodimensional electron system is an important parameter determining the width of the resonance.