Super Resolution Chemical Imaging with Plasmonic Substrates
We demonstrate super resolution chemical imaging with plasmonic nanoholes via surface enhanced Raman spectroscopy (SERS) Due to large field enhancements, blinking behavior of SERS hot spots was observed and processed using a stochastic optical reconstruction microscopy (STORM) algorithm. This enabled localization to within 10 nm and high resolution imaging. However, illumination of the sample with a static laser beam produced only SERS hot spots in fixed locations, leaving noticeable gaps in the final images. By randomly altering the phase profile of the incident beam with a simple optical diffuser, the hot spots were shifted across the plasmonic surface to illuminate different areas of the sample, thereby rendering a final image without the gaps. A tunable band pass filter was used to preserve spectral information, allowing chemical contrast imaging. Images were then compared to those obtained with a scanning electron microscope. Finally, we show that super resolution SERS images can also be obtained wi.