Large field-of-view plasmonic scattering imaging and sensing of nanoparticles with isotropic point-spread-function.

Label-free optical imaging and sensing of single nanoparticles are vital for fundamental research, disease diagnosis, and nanomaterial studies. Surface plasmon resonance microscopy (SPRM) is a label-free detection technology which is widely used in the detection of single nanoparticles. However, conventional SPRM suffers from poor spatial resolution, a limited field-of-view, system complexity, and high operating costs. In this study, we introduce a compact, low-cost, and large field-of-view chip-based plasmonic scattering microscopy (Chip-PSM). Compared with SPRM, Chip-PSM retains high detection sensitivity and in situ label-free analysis capability, while offering a larger field-of-view, an isotropic point-spread-function and higher spatial resolution. With these advantages, Chip-PSM enables detecting and imaging dielectric nanoparticles, gold nanoparticles, and biological samples. Additionally, the hygroscopic growth dynamics of aerosol nanoparticles and the chemical reactions occurring on nanocrystals are successfully characterized via Chip-PSM. We anticipate that the proposed Chip-PSM will have broad applications across many scientific fields, including physics, chemistry, and atmospheric sciences.