Resonator modes in a two-dimensional quasi-stadium laser diode with concave end mirrors

We investigated the resonator modes of a two-dimensional quasi-stadium laser diode with concave end mirrors by using an extended Fox-Li mode calculation method. The resonator modes were found to have a significant wavelength dependence due to beam interference in the laser cavity. A scar mode was observed in which optical beams are localized on unstable periodic orbits at a wavelength at which the diffraction loss has a local minimum. These results are similar to those obtained for a quasi-stadium laser with convex end mirrors, but we found that using a concave mirror does not produce intensely focused spots in the laser cavity, making it suitable for high-power operation.