One-Dimensional Moiré Flat-Band Nanolasers with Stable Single-Mode Emission

Stable single-mode lasing emission has long been pursued as a persistent goal in photonics, but its realization remains challenging. Here, we present robust single-mode moiré nanolasers in the telecom C-band, enabled by spatially separated flat-band localization in a one-dimensional moiré photonic crystal nanobeam. The fabricated device, constructed by two moiré supercells, maintains single-mode operation at high excitation power up to 64.4× lasing threshold, constrained by the available pump source. Additionally, dual moiré flat-band modes are selectively excited for lasing emission in a triple-supercell nanocavity, owing to negligible optical field overlap. The demonstrated one-dimensional moiré nanolasers, holding distinctive features including sustained single-mode operation, high temperature stability, and small mode volume, offer crucial insights into moiré physics of active photonic systems and highlight flat-band engineering as a promising avenue for nanoscale light manipulation.