Investigation of Equivalence between Non-Resonant Raman Excitation Spectroscopy and Conventional Raman Spectroscopy

As spontaneous Raman spectroscopy is demonstrated to be viable for many applications, it is still held back by its inherently low signal and typically extended acquisition time. While several techniques can overcome this by enhancing the scattered signal to quicken acquisition, a parallel field that quickens spectral acquisition using instrumentation has received less focus. In principle, Raman spectra could be obtained by tuning the excitation wavelength and measuring the Raman signal at a fixed wavelength using a single-pixel detector. Before exploring the potential of quicker acquisition, it is important to first study the equivalence of Raman Excitation Spectroscopy and conventional Raman Spectroscopy experimentally. We demonstrate the equivalence between the two techniques for biological and non-biological samples by measuring Raman Excitation Maps. Additionally, we explore the interpolation of low-resolution excitation spectra using excess information in the maps for higher resolution excitation spectra. This work, together with current progression in fast tunable lasers and highly sensitive single-pixel detectors, provides a promising prospect for dedicated Raman Excitation Spectroscopy instruments to be developed.