Magnetoplasma effects in a quasi-three-dimensional electron gas

Far-infrared magnetotransmission measurements on a quasi-three-dimensional modulation-doped semiconductor structure are reported in the frequency region of the bulk plasmon. When a magnetic field is applied tilted with respect to the film plane, two branches appear in the excitation spectrum resulting from the coupling between cyclotron resonance and the plasma oscillations perpendicular to the film plane. The experiment demonstrates the connection between the depolarization-shifted intersubband transitions and the bulk plasma resonance.