Inelastic light scattering in two-dimensional systems in high magnetic fields.

We review recent resonant inelastic light scattering research carried out in modulation doped GaAs-(AlGa)As quantum well heterostructures. The valence subband states are probed as a function of applied magnetic field by measurements of the transitions of high mobility two dimensional hole gases. In the case of two dimensional electron gases in high magnetic fields normal to the plane we observe combined Landau level- intersubband excitations, Landau level transitions and quasi- 3D magnetoplasmons.