Snapshot Hyperspectral Imaging (Shi) For Revealing Irreversible And Heterogeneous Plasmonic Processes

Plasmon-mediated processes provide unique opportunities for selective photocatalysis, photovoltaics, and electro-chemistry. Determining the influence of particle heterogeneity is an unsolved problem because often such processes introduce irreversible changes to the nanocatalysts and/or their surroundings. The challenge lies in monitoring heterogeneous non equilibrium dynamics via the slow, serial methods that are intrinsic to almost all spectral acquisition methods with suitable spatial and/or spectral resolution. Here, we present a new metrology, snapshot hyperspectral imaging (SHI), that facilitates in situ readout of the tube lens image and first-order diffraction image of the dark-field scattering from many individual plasmonic nanoparticles to extract their respective spectra simultaneously. Evanescent wave excitation with a supercontinuum laser enabled signal-to-noise ratios greater than 100 with a time resolution of only 1 ms. Throughput of similar to 100 simultaneous spectra was achieved with a highly ordered nanoparticle array, yielding a spectral resolution of 0.21 nm/pixel. Additionally, an alternative dark-field excitation geometry utilized a combination of a supercontinuum laser and a reflecting objective for polarization controlled SHI. Using a simplified version of SHI, we temporally resolve on the millisecond time scale the heterogeneous kinetics of an electrochemical surface redox reaction for many individual gold nanoparticles simultaneously.