Advances in submicron technology make it possible to realize man-made low-dimensional electronic systems with quantum confined energy states. Superimposing lateral potential onto two-dimensional electron systems for example in AlGaAs-GaAs systems allows one to prepare quantum wires and dots. We will discuss modulation-doped systems. Then, with typical confinement energies in the meV regime, far-infrared and resonant Raman spectroscopy give direct access to the quantum confined energy levels of the systems. One is now approaching the limit to prepare quantum dots with well defined small numbers of electrons per dot, N=3D 1, 2, 3... It becomes thus possible to perform a kind of ``atomic'' spectroscopy in these systems.