Lasing Enhanced Surface Plasmon Resonance Sensing

The resonance phenomena of surface plasmons has enabled development of a novel class of noncontact, real‐time and label‐free optical sensors, which have emerged as a prominent tool in biochemical sensing and detection. However, various forms of surface plasmon resonances occur with natively strong non‐radiative Drude damping that weakens the resonance and limits the sensing performance fundamentally. Here we experimentally demonstrate the first lasing‐enhanced surface plasmon resonance (LESPR) refractive index sensor. The figure of merit (FOM) of intensity sensing is ~84,000, which is about 400 times higher than state‐of‐the‐art surface plasmon resonance (SPR) sensor. We found that the high FOM originates from three unique features of LESPR sensors: high‐quality factor, nearly zero background emission and the Gaussian‐shaped lasing spectra. The LESPR sensors may form the basis for a novel class of plasmonic sensors with unprecedented performance for a broad range of applications.