Molecular ruler based on concurrent measurements of enhanced Raman scattering and fluorescence.

We report a way to assess the separation between a molecule and a metal surface on account of both Raman scattering and fluorescence intensities measured simultaneously. This approach has no need for an accurate quantity of molecules and bears 1 nm resolution. Its distance sensitivity is experimentally demonstrated in the case of dye molecules lying on a gold surface with a polymer spacer layer in between and is compared with theoretical prediction.