Photonic Bandgap Fiber Microlaser with Dual‐Band Emission for Integrated Optical Tagging and Sensing

Abstract Lasers are emerging as novel photonic tags for single‐cell labeling, anticounterfeiting, and encryption technology due to their narrow linewidth, high spectral multiplexing capacity, and superior stimuli‐responsiveness. These laser‐encoded photonic tags mostly distinguish the heterogeneity but do not yet provide both tagging and sensing of biosamples, which is highly desirable for disease screening. Here, a photonic bandgap (PBG) fiber microlaser that works as a 2D tag and an immunosensor is developed. The tubular PBG structure allows strong light–matter interaction and supports dual‐band lasing in the same optical fiber, enabling massive biosample tagging and sensitive biodetection. By encoding the random resonant peaks in the short‐wave band and multiplexing in the spatial domain, a 2D laser tag is generated with a large encoding capacity (>2 8500 ). Immunosensing of microalbumin is realized by using the periodic resonant peaks in the long‐wave band, and a limit of detection of 0.06 ng µL −1 is achieved. This work is inspiring for the development of high‐performance, multifunctional integrated devices for disease screening.