Raman scattering1 is a potent approach for unambiguously figuring out the presence of tiny portions of various substances, because it accesses the wealthy and distinctive spectral fingerprint of a given substance’s vibrational spectrum whereas working within the optical vary, the place each highly effective laser sources and delicate detectors can be found. Nonetheless, being a 3rd order nonlinear course of, Raman scattering suffers from very low effectivity, limiting sensitivity. Totally different strategies have been used to reinforce sensitivity of Raman detection. Amongst them is utilizing resonant Raman scattering2, however that requires a pump laser to be tuned near the molecule’s digital transition, which isn’t at all times attainable. A strong enhancement approach broadly used right this moment is floor enhanced Raman scattering3 (SERS) the place the pump subject is strongly enhanced in a sub-wavelength dimension area (or ‘sizzling spot’) close to a nanostructured metallic floor. As well as, in SERS the density of photon states on the scattered wavelength is enhanced, inflicting additional effectivity enhancement as a result of Purcell impact.
