Resonant Third-Order Nonlinearity of Quasi One- and Zero-Dimensional Electron Systems

The invention of semiconductor multi-quantum wells and the following discovery of large optical nonlinearities in them [1] have started a substantial research effort into the properties of such two-dimensional quantum confined systems. Furthermore the question of further reducing the electron dimensionality and the associated scaling laws [2] has arisen. By reducing the electron dimensionalities by confining them physically in two and three dimensions beyond their de-Broglie wavelength, the situation of the idealized "particle-in-the-box" is realized. Associated with this behavior is an increase in the exciton binding energy (observable at room temperature) and in oscillator strength, and hence also an increase of the optical nonlinearity arising from the saturation of this transition. By suitable choice of chemical systems this low dimensional behavior can be experimentally approached.