OPTICAL-ABSORPTION IN A 2-DIMENSIONAL QUANTUM POINT-CONTACT

We calculate the optical absorption of a quantum point contact. We find that the absorption in the very center of the microconstriction is clearly separated in frequency from the absorption in the wide contact regions. Therefore optical point contact spectroscopy is possible and can be very useful in characterizing the shape of the laterally confining potential. We show how two different types of potentials produce entirely different spectra. Further, optical point contact spectroscopy is found to be sample independent since the microconstriction geometry has practically no influence on the absorption, as long as we consider adiabatic geometries.