Ultra‐Compact Twisted Photonic Crystal Semiconductor Nanolasers with Ultra‐Small Mode Volumes

ABSTRACT The twisted nanocavity, formed by stacking photonic crystals, enables extreme in‐plane light confinement and allows for active tuning of optical modes by adjusting the twist angle and manipulating the shape of central unit cell. Here, we present a straightforward method for constructing ultra‐compact twisted photonic crystal nanocavities with ultra‐small mode volumes for lasing emission in the 1550 nm telecom band. The fabricated twisted photonic crystal nanolasers exhibit a systematic change in lasing wavelengths depending on the lattice constant and the radius of airhole. Furthermore, to reduce the mode volume and suppress multi‐wavelength emission under high input powers, a fully degeneracy‐lifted optical mode is engineered by breaking the rotational symmetry and incorporating a slotted airhole into the twisted nanocavity. Optimized lasing performance with stable single‐mode operation and an ultra‐small mode volume of 0.052 has been achieved in the twisted slotted photonic crystal nanolaser. Our work provides a practical method for easily constructing robust nanolasers that simultaneously achieve an ultra‐small mode volume and single‐mode emission, which paves the way for developing high‐performance nanoscale coherent light sources for densely integrated photonic chips.