Mode control in photonic crystal surface emitting lasers through external reflection

In this paper, we show the effect of lateral external optical feedback on an all semiconductor photonic crystal surface emitting laser (PCSEL). Initially, a PCSEL is grown and fabricated with a square lattice of triangles, the device is shown to operate electrically driven at room temperature under continuous wave condition. We investigate, theoretically and experimentally, the effect of lateral feedback on the performance of photonic crystal lasers. Demonstrating a reduction in mode competition and a modification to spatial mode distribution, opening routes to all electronic beam shaping and divergence control