Ambient‐Stable NIR Nanolasing: Monolithic Integration of PbS CQDs on a Silicon Photonic Platform

Abstract Nanolasers based on colloidal quantum dots (CQDs), while transformative in the visible spectrum, face critical roadblocks in the near‐infrared (NIR) regime due to material instability under ambient conditions and ultrafast Auger recombination in large NIR CQDs. Here, these limitations are addressed through zinc‐doped PbS CQDs that suppress nonradiative decay, integrated with compact high‐Q silicon nanobeam cavities to leverage the Purcell effect for efficiently guiding spontaneous emission into laser modes, thereby significantly reducing the threshold power. This work demonstrates a monolithic CQD‐integrated silicon photonic platform that achieves NIR lasing under pulsed optical pumping, featuring a record narrow linewidth of 0.29 nm (0.15 meV) at 1579.20 nm and an ultralow threshold of 127 µJ cm ⁻² . Notably, under continuous‐wave (CW) pumping, the device exhibits cavity‐filtered spontaneous emission with a sub‐nanometer linewidth across the 1350–1600 nm spectrum. This emission showcases <6% peak power decay over 15 h at 300 K, robust performance up to 360 K, and negligible degradation after 250 days of ambient storage. By monolithically integrating solution‐processed CQDs with CMOS‐compatible silicon photonics, this platform establishes a reliable, scalable, and low‐cost route toward multiwavelength on‐chip nanolaser arrays in the NIR regime, unlocking transformative potential for compact photonic technologies in imaging, sensing, and communications.