SERDS to Silence Fluorescence Revealing Hidden Raman Signals with New Dual-line Laser

Raman spectroscopy is a powerful analytical technique valued for its non-invasive sampling, high level of molecular specificity and spatial resolution, making it ideal for applications such as pharmceutical and semiconductor process monitoring, material
science, and biomedical research. However, its utility is often hindered by the presence of strong fluorescence emission from the sample, which hides the inherently much weaker Raman scattering signal.

Shifted Excitation Raman Difference Spectroscopy (SERDS) can offer a solution to this problem by effectively eliminating the background fluorescence. The technique uses two narrow-linewidth lasers with slightly different emission wavelengths. As the Raman peaks spectrally follow the excitation while fluorescence remains largely unchanged, subtracting the two spectra effectively removes the fluorescence background, revealing the underlying Raman signal. This article outlines the principles and practical benefits of SERDS and discusses the laser requirements essential for reliable performance.