Experimental study of disorder in a semiconductor microcavity - art. no. 165309

A detailed study of the structural disorder in wedge semiconductor microcav ities (MC's) is presented. We demonstrate that images of the coherent emiss ion from the MC surface can be used for a careful characterization of both intrinsic and extrinsic optical properties of semiconductor NIC's. The pola riton broadening can be measured directly, avoiding the well-known problem of inhomogeneous broadening due to the MC wedge. A statistical analysis of the spatial line shape of the images of the MC surface shows the presence o f static disorder associated with dielectric fluctuations in the Bragg refl ector. Moreover, the presence of local fluctuations of the effective cavity length can be detected with subnanometer resolution. The analysis of the r esonant Rayleigh scattering (RRS) gives additional information on the origi n of the disorder. We find that the RRS is dominated by the scattering of t he photonic component of the MC polariton by disorder in the Bragg reflecto r. Also the RRS is strongly enhanced along the [110] and [1 (1) over bar0] directions. This peculiar scattering pattern is attributed to misfit disloc ations induced by the large thickness of the mismatched AlGaAs alloy in the Bragg mirrors.