Super-Resolution Raman Scattering Imaging Enabled by Rough Metal Films

A super-resolution Raman scattering microscopy technique is demonstrated by combining localized surface plasmon-based structured illumination microscopy with the blindSIM algorithm. This approach enables super-resolution Raman scattering imaging of dielectric nanoparticles with sub-100 nm resolution. The technique leverages the surface-enhanced Raman scattering effect of rough silver films to generate near-field speckle patterns, enabling subdiffraction-limited optical sampling and enhanced Raman signals. The method demonstrates the excitation/emission modulation between emitters separated by subdiffraction distances. Experimental results reveal that background subtraction for Raman images from polystyrene beads generates image contrasts predominantly consisting of Raman-shifted photons. The enhanced signal-to-noise ratio obtained from 80 nm polystyrene beads proves sufficient for applying the blindSIM algorithm. The result presents a remarkable resolution enhancement, surpassing the diffraction limit by 4.4 times and successfully resolving 80 nm dielectric nanoparticles. This approach represents a significant advancement in label-free super-resolution imaging, offering potential applications in various fields of microscopy and materials science.