Ocean Optics MMS Raman - Manual (Page 19)

Appendix B
Introduction to Multimodal
Multiplex Sampling
Introduction
This appendix describes a new generation of spectrometer technology that employs multimodal multiplex
sampling (MMS). The performance of a spectrometer based on MMS is then compared to conventional
slit and fiber input spectrometers.
Dispersive spectrometers come in two basic designs: scanned-grating monochromators and static grating
designs with detector arrays. With the availability of inexpensive linear detectors and charge coupled
devices (CCDs) in the UV/Visible/NIR region, dispersive spectrometers are moving away from scanned-
grating designs to static implementations. Static implementations are preferred for their single shot
measurements, fast data acquisition times and
high mechanical reliability. A typical static
grating design is shown in Figure 1.
Most dispersive designs use a fiber based input
while some implement a vertical slit which is
binned on the detector to increase sensitivity. In
such traditional designs, there is an inherent
tradeoff between resolution and light throughput.
While spectral resolution increases as slit width
decreases, a narrow input slit greatly limits
photon throughput and likewise, measurement
sensitivity.
Centice is introducing a new patent pending
spectrometer design based on an optical sensing
technology originally developed at
Duke University called Multimodal Multiplex
Sampling (MMS).
Figure 1: A traditional static grating spectrometer
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