Intra-laser-cavity sensing with a dual-wavelength distributed-feedback laser

摘要

An integrated intra-laser-cavity microparticle sensor based on a dual-wavelength distributed-feedback channel waveguide laser in Al2O3:Yb3+ on silicon is demonstrated. Real-time detection and accurate size measurement of single micro-particles with diameters of 1-20 μm are achieved. A limit of detection of ~500 nm is deduced. The sensing principle relies on measuring changes in the frequency difference between the two longitudinal laser modes as the evanescent field of the dual-wavelength laser interacts with micro-sized particles on the waveguide surface.