Switch from mono-to multi-mode polariton laser in GaN ridge waveguide

We report a polariton laser in a GaN ridge waveguide with a switching from mono to multi-mode laser operation with temperature. The study of the free spectral range between the modes first leads to the unambiguous proof that the polaritons are in a regime of strong coupling. Above 150K, during the passage to the multi-mode laser, a flattening of the FSR demonstrates a synchronization of the modes. These results therefore suggest additional harmonic mode-locking studies in polariton waveguide.