Optical investigations of bulk and multi-quantum well nitride-based microcavities

The light-matter coupling has been investigated in λ/2 and in λ-GaN microcavities. It is shown that the optical properties of the cavity are affected by the strong absorption in the GaN active layer when its thickness increases. Results obtained on a microcavity including GaN/AlGaN multi-quantum well (MQW) are also reported and the oscillator strengths of excitons are deduced from the fit of reflectivity spectra. Nevertheless improvement of the design and material quality of the MQW microcavity will be necessary to observe the strong coupling.