Ocean Optics MMS Raman - Manual (Page 24)

B: Introduction to Multimodal Sampling
Signal to Noise Ratio
A better understanding of the performance advantage of MMS spectroscopy can be obtained by
comparing spectra from real samples. Raman spectra of Toluene are measured with three different
configurations and an integration time of 2 seconds: fiber-input (Figure 6), vertically binned slit (Figure
7), and MMS (Figure 8), where all other system parameters are equivalent. These data show a noticeable
signal to noise ratio advantage of MMS. The specific advantage depends on the source noise
characteristics, detector noise characteristics and the spectral content of the source, and therefore cannot
be generalized for all cases. However, MMS spectrometers always offer superior signal to noise
performance versus these conventional designs.
Additional Raman spectra obtained with the MMS spectrometer are shown in Figures 9 and 10.
Figure 7: Raman spectrum of toluene
measured with a slit.
Figure 8: Raman spectra of toluene
measured with MMS.
Figure 9: Raman spectrum of Tylenol with MMS
spectrometer (20s integration)
Figure 10: Raman spectrum of toluene with MMS
spectrometer (20s integration)
Figure 6: Raman spectrum of
toluene with a pinhole aperture
.
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