Spectral interferometry of semiconductor nanostructures

Fourier transform spectral interferometry is applied to measure both amplit ude and phase of the electric field in different types of semiconductor nan ostructures, thus determining the real and imaginary parts of the dielectri c function, The importance of measuring the phase is shown and discussed in three studies. First, the phase measurement is used to access directly the refractive index across excitonic resonances in bulk GaAs and AlGaAs-GaAs quantum wells, with unprecedented resolution. Second, we measure the densit y dependence of the full dielectric function across a Fano resonance in bul k GaAs and show that this allows us to obtain some information on the colli sional broadening of the usually hidden linewidth of the coupled esciton/co ntinuum. Third, the phase is studied in a complex heterostructure, a semico nductor microcavity. We investigate and discuss the effect of the cavity de tuning and of the excitation density.