Surface-enhanced Raman spectroscopy with a laser pointer light source and miniature spectrometer

The initial steps toward a miniature, field portable sensor based on surface-enhanced Raman spectroscopy (SERS) are presented. It is demonstrated that a low-cost miniaturized Raman system can be used in place of a larger, higher-cost conventional Raman system. This system was developed by sequentially replacing components of a laboratory scale Raman spectroscopy system with smaller, lower-cost, commercially available components. For example, a green laser pointer was used as the excitation source, a reflectance probe fiber-optic cable was used for laser delivery and collection, and a compact card-based spectrometer was used for dispersion and detection. Spectra, collected with the laser pointer Raman system, are presented of a resonant (Rhodamine 6G) and a non-resonant (trans-1,2-bis(4-pyridyl)ethylene) molecule as well as a self-assembled monolayer (1-decanethiol). Small, low-cost sensors are in demand for a variety of applications, and SERS is positioned to contribute significantly with its remarkable sensitivity and molecular specificity.