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Visible and Near Infrared (NIR) spectroscopy finds use in a number of applications
including security, biomedicine, military, materials science, and materials processing areas to
name a few. Visible red and NIR ranges are particularly valuable for in vivo studies because
photons in this range have very low potential energy and are hence usually considered noninvasive.
Integrated spectrometers operating in the NIR spectral range can have high resolution
and transmission, low cost, and can exhibit low noise depending on detection properties and
light throughput. Optical and NIR spectrometers in this and other work have been shown to
operate under normal environmental conditions (such as temperature, atmospheric gases, and
humidity) and do not generally require vacuum operation.
In this research, the “spectral analysis” sections of a micro-mirror based Reflective
Adaptive Slit (RAS) with single InGaAs photodiode spectrometer has been studied and
compared to a conventional InGaAs array detector based spectrometer. It should be noted that
in both approach, either RAS with single photodiode or Conventional Array Detector (CAD)
based spectrometry, the spectrometer system requires a dispersive element (prism or grating)
or filter to separate the polychromatic light beam under analysis. If the system is a so called
“active” system, a light source is also needed. In this work we test, model, and compare a
Reflective Adaptive Slit micro-mirror based single element photodiode system to a commercial
array detector based spectrometer. Within the context of the Reflective single photodiode
micro-mirror Slit spectrometer, we are establishing a set of optical requirements to ideally cover
a number of applications. In addition to experimental performance comparisons between the
spectrometer approaches, we will report on the performance requirements and environmental
issues for these NIR spectrometers.
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