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High Spectral Resolution Raman Measurements Using Light-Emitting Diode as Excitation Based on Weighted Spectral Reconstruction Method

Raman spectroscopy is a spectroscopic technique that can provide rich biochemical information about the sample through the inelastic scattering between monochromatic light and molecular vibrations, thus a narrow bandwidth and costly laser is typically required. Although the replacement of laser to light-emitting diode (LED) can reduce the cost significantly, spectral resolution degrades seriously and a large amount of Raman fingerprint information is lost due to the overlaps of Raman peaks. In this study, a weighted spectral reconstruction method was developed to retrieve high quality Raman spectrum from the Raman measurements using LED as the excitation, in which the LED based Raman measurements were numerically synthesized from the Raman spectra acquired by the conventional laser-based Raman spectroscopy systems. The proposed weighted spectral reconstruction method was numerically test on the synthesized LED based Raman measurements from 25 agar phantoms, 50 blood serum samples, and 56 cell samples, respectively. According to the results, the restored Raman spectra are in excellent agreement with the conventional Raman spectra, and the differences are always less than 2% in all test samples. Therefore, Raman measurements using LED as excitation combined with weighted spectral reconstruction method demonstrate significant potential in accurate and high spectral resolution Raman measurements, which promotes a cost-effective Raman setup while preserve the most important spectral and biochemical information.