An apparatus and related methods for spectroscopic analysis of analyte molecules is described. The analyte molecules are disposed near a metallic film that is positioned between a first medium on a first side and a second medium on a second side, the second medium being of higher refractive index than the first medium. A radiation source provides excitation radiation that propagates through the second medium toward the metallic film. The second medium and the metallic film are positioned in evanescent communication with respect to the excitation radiation, and the metallic film comprises lithographically patterned features designed to intensify surface plasmon resonance along the metallic film to promote the emission of Raman radiation from the analyte molecules. A radiation detector detects the Raman radiation emitted from the analyte molecules.