Feel like you’re missing Raman signal – 405 nm can help see more

In recent years, Raman spectroscopy has attracted worldwide attention as an analytical technique applicable for a wide range of markets, from materials and life sciences applications to point of care analysis, industrial screening to pure R&D. Thanks to compact laser sources, high sensitivity cameras and ultra-light compact spectrometers, Raman systems in recent years have been further miniaturized with increased sensitivity while becoming multifunctional. In this post, we show what performance improvements can be achieved by using a 405 nm laser compared to the longer wavelength lasers used more conventionally.

Not absent, just buried

A general challenge in Raman spectroscopy is that the inherently weak Raman signal is often hidden by the influence of fluorescence (Fig 1). In order to minimize the effects of fluorescence, lasers in the NIR (785 nm – 1064 nm) are often used. However, since the Raman scattering intensity is inversely proportional to the fourth power of the laser wavelength, longer NIR wavelengths have the disadvantage that the Raman scattering intensity decreases. In addition, since the sensitivity of silicon sensors decreases in the wavelength region >800 nm, an expensive InG