Spectral hole burning in intersubband absorption bands of quantum-well-structures

Abstract

Transient hole burning experiments on a picosecond time scale give a convincing proof of inhomogeneous broadening of intersubband absorption bands for the first time. At excitation intensities of 400 kW/cm2 population holes of ∼60 cm-1 widths are found in narrow n-modulation doped GaAs/Al0.35Ga0.65As quantum well structures. At intensities of a few MW/cm2 "holes" in the absorption spectra due to a χ(3) effect are observed.