Surface enhanced coherent anti-stokes Raman scattering on nanostructured gold surfaces.

Coherent anti-Stokes Raman spectroscopy (CARS) is a well-known tool in multiphoton imaging and nonlinear spectroscopy. In this work we combine CARS with plasmonic surface enhancement on reproducible nanostructured surfaces. We demonstrate strong correlation between plasmon resonances and surface-enhanced CARS (SECARS) intensities on our nanostructured surfaces and show that an enhancement of ∼10(5) can be obtained over standard CARS. Furthermore, we find SECARS to be >10(3) times more sensitive than surface-enhanced Raman Spectroscopy (SERS). We also demonstrate SECARS imaging of molecular monolayers. Our work paves the way for reliable single molecule Raman spectroscopy and fast molecular imaging on plasmonic surfaces.