Infrared absorption spectroscopy offers direct access to the vibrational signatures of molecular structure. Although
absorption cross sections are nearly 10 orders of magnitude larger than the Raman cross sections, they are small in
comparison with those of fluorescent labels. Sensitivity improvements are therefore required in order for the method to
be applicable to single molecule/monolayer studies. In this work, we demonstrate a plasmon enhanced vibrational
spectroscopy technique which allow for the measurement of molecule specific signatures at the monolayer level.
Specifically, we show 4-5 order of magnitude enhancement of the amide-I and II backbone signature of protein
monolayers, the signal resulting from only zeptomole quantities of molecules.