LAUSR

We present the concept of nonlinear plasmonic sensing approach for rapid, sensitive and label-free detection of mercury. Nonlinear plasmonic sensing of mercury relies on a systematic combination of nonlinear optics (NLO) with well-known concepts of amalgamation chemistry and plasmonic properties of gold nanorods. Exploiting the extreme sensitivity of NLO process toward Hg-induced change in the local electric field of plasmonic nanorods, we succeed in improving the limit of detection (LOD) of mercury by 2-3 orders of magnitude as compared to the commonly used linear localized surface plasmon resonance (LSPR) based sensing. Using our method, an LOD of as low as 58 picomolar (11 ppt) has been achieved with high selectivity. Nonlinear plasmonic sensing aproach is found to work excellent for detecting mercury in real samples like blood plasma.