Two‐Photon Pumped Wavelength‐Tunable Single‐Mode Plasmonic Nanolaser with Ultralow Threshold

Abstract Nonlinear optics play an important role in laser technology, optical communication, integrated optics, and other fields. However, conventional two‐photon lasing faces challenges such as high thresholds and large size, which hinder the miniaturization of lasers. In this study, the structure of single‐crystal Au/Al 2 O 3 /CsPbBr 3 (ScAu/Al 2 O 3 /CPB) is constructed to achieve two‐photon pumped frequency upconversion single‐mode plasmonic lasing. The strong spatial confinement and near‐field enhancement of surface plasmons in metals enable the plasmonic lasing mode output in a hybrid nanocavity, significantly reducing the lasing threshold. Additionally, by applying external mechanical strain, the resonant wavelength of the lasing mode is dynamically regulated, further reducing the threshold to 0.48 mJ cm −2 based on piezo‐electronic effect. These results provide an effective strategy for all‐optical integration and the development of smaller, faster, and more efficient nanophotonics devices.