Continuous-Wave Pumped Monolayer WS₂ Lasing for Photonic Barcoding

Micro/nano photonic barcoding has emerged as a promising technology for information security and anti-counterfeiting applications owing to its high security and robust tamper resistance. However, the practical application of conventional micro/nano photonic barcodes is constrained by limitations in encoding capacity and identification verification (e.g., broad emission bandwidth and the expense of pulsed lasers). Herein, we propose high-capacity photonic barcode labels by leveraging continuous-wave (CW) pumped monolayer tungsten disulfide (WS₂) lasing. Large-area, high-quality monolayer WS₂ films were grown via a vapor deposition method and coupled with external cavities to construct optically pumped microlasers, thus achieving an excellent CW-pumped lasing with a narrow linewidth (~0.39 nm) and a low threshold (~400 W cm^-2) at room temperature. Each pixel within the photonic barcode labels consists of closely packed WS₂ microlasers of varying sizes, demonstrating high-density and nonuniform multiple-mode lasing signals that facilitate barcode encoding. Notably, CW operation and narrow-linewidth lasing emission could significantly simplify detection. As proof of concept, a 20-pixel label exhibits a high encoding capacity (2.35 × 10¹⁰⁸). This work may promote the advancement of two-dimensional materials micro/nanolasers and offer a promising platform for information encoding and security applications.