Strong coupling of light with a and B excitons in GaN microcavities grown on silicon

We present experimental results demonstrating strong-light matter coupling at low and room temperature in bulk GaN microcavities with epitaxial (Al,Ga)N Bragg mirrors grown on silicon (111). At low temperature, the strong coupling of both the A and B excitonic features of GaN with the cavity mode is clearly resolved in the microcavity. At room temperature a Rabi energy of 50 meV is observed and well reproduced using transfer-matrix reflectivity calculations describing the interaction of both the A and B excitonic states with the photonic mode.