Resonant Faraday rotation in a semiconductor microcavity

Faraday rotation at quantum well exciton resonances is enhanced in a microcavity due to multiple round- trips of light between the mirrors when the cavity mode is strongly coupled to the exciton and is accompanied by resonant redistribution of the signal between right- and left-circular polarization. A resonant Faraday rotation of about 3$\ifmmode^\circ\else\textdegree\fi{}$ is detected in reflected light from an (In,Ga)As/GaAs quantum well microcavity in an 11.25 T magnetic field when the cavity mode is resonant with either heavy- or light-hole excitons.