Lasing on higher-order whispering gallery modes at room temperature

We report a direct method to observe higher-order whispering gallery modes in vertical cavity surface emitting lasers (VCSELs) at room temperature. Instead of introducing any defect mode, we show that suppression of lower-order cavity modes can be achieved by destroying vertical reflectors with a surface micro-structure. Perfect whispering gallery modes with an azimuthal number as large as 41 are observed in experiments through collecting near-field radiation patterns, as well as in numerical simulations.