Plasmonic patterned wide-field gap mode mechanism for surface enhanced Raman imaging

The gap mode enhancement of metal nanoparticles is introduced into wide-field Raman microscopic imaging, where it produces a more efficient Raman scattering map compared with the scanning mechanism based on a single nanoparticle. Patterned surface plasmon illumination technique is employed to extend spatial resolution of the wide-field Raman imaging to 133 nm achieved by a modified total internal reflection microscope. The images by different Raman shifts are extracted by using narrow band pass dielectric filters. The technique can serve as a robust tool for wide-field surface enhanced Raman imaging.