Far-infrared spectroscopy of a two-dimensional electron gas in a tunable, periodically modulated magnetic field

We report on the first infrared optical measurements of a two-dimensional electron gas (2DEG) in the presence of an external periodically modulated perpendicular magnetic field, realised using epitaxial regrowth to produce a corrugated quantum well (QW). Two active modes are observed, with relative intensities and resonance frequencies depending on the amplitude of the magnetic field modulation as well as on the total external magnetic field. The two modes are interpreted as being magnetoplasmons coupled by the presence of the magnetic field modulation. The magnetoplasmons band structure calculation has been used to describe the experimental data. The agreement between theory and experiment is excellent. (C) 2000 Elsevier Science B.V. All rights reserved.