Скачать или смотреть Super Spectral Resolution Raman Spectroscopy

Raman spectroscopy is an extremely powerful laser-based method for characterizing materials based on their unique inelastic scattering spectrum. Ultimately, the power of the technique is limited by the resolution of the spectrometer. Here we introduce Super-Spectral-Resolution Raman Spectroscopy (SSR-RS), a method which greatly improves the spectral resolution of the spectrometer. A Fabry–Perot (F-P) Etalon filter mounted on an angle-tunable motor, is added to the classical micro-Raman setup, and Raman spectra are automatically acquired for many different angles of the F-P filter as shown in Figure 1(a). In previous published super-resolution Raman experiments, the mirror distances (d) with the F-P were varied [1, 2]. Here, the F-P etalon itself is fabricated as monolithic structure, plane and parallel by design through a set of innovations developed by Light-Machinary. With a low-resolution grating of 150 g/mm, which by itself exhibited a best-case resolution of 40 cm-1, we applied the SSR-RS technique to diamond to obtain the ”Inter-theta-gram” data shown in Figure 1(b), from which a linewidth fit parameter of less than 1 cm-1 was derived. To baseline SSR-RS, we used the super-spectral-resolution method to extract the linewidth of the laser excitation itself and obtained a laser linewidth of better than 0.007 cm-1. In essence, the modelling aspect of SSR-RS is a kind of “point-spread-function” fitting of the spectrum. Further investigations were carried out on the spectra of a natural diamond compared to a lab-grown diamond, where in both cases, a spectral resolution improvement of at least 40X of the original spectrum has been obtained. Using SSR-RS, we were able to observe differences between natural vs. lab-grown diamond due to different Raman shifts and Raman shift linewidths.