Room-temperature normal-mode coupling in a semiconductor microcavity utilizing native-oxide AlAl/GaAs mirrors

A GaAs/AlAs microcavity containing six InGaAs quantum wells was grown, and the sample was then etched via chemically‐assisted ion‐beam etching to form 50‐μm‐diam cylindrical mesas. The formation of native oxides, accomplished by baking the samples at 400 °C in the presence of a pressurized N2/H2O vapor line, lowered the refractive index of the AlAs layers to 1.5. The higher refractive index contrast more effectively confined the intracavity field, leading to well‐resolved reflectivity dips with an exciton‐polariton splitting of 6.72 nm=9.44 meV at room temperature.