Wavelength-tunable photonic crystal nanolaser arrays enabled by twist-angle engineering.

Twisted nanocavities, constructed by stacking bilayer photonic crystals, provide the twist angle as an additional geometric parameter for tailoring resonant wavelengths. Here, we demonstrate systematic lasing-wavelength engineering in the twisted photonic crystal nanolaser array by continuously varying the twist angle, where increasing the twist angle produces a blueshift in the lasing wavelength. By jointly varying the twist angle and lattice constant, broad wavelength tunability over ~90 nm is achieved. Compared with conventional defect-engineered photonic crystal nanolasers, twist-angle-based wavelength tuning in twisted nanolasers avoids the need for rigorous optimization of multiple structural parameters and offers a simplified wavelength tuning strategy toward multi-wavelength on-chip light sources.