Single-mode lasing of GaN nanowire-pairs

Stable single-mode lasing operation from a pair of coupled GaN nanowires is demonstrated through optical pumping. GaN nanowires with different lengths were placed side-by-side in contact to form a coupled cavity through nanoprobe manipulation. Unlike individual nanowire lasers, which operate in a combined multiple transverse and multiple longitude mode oscillation, a coupled nanowire-pair provides a mode selection mechanism through the Vernier effect, which can strongly enhance the free spectrum range between adjacent resonant modes and generate a stable single-mode operation with a high side-mode suppression ratio.