A portable NIR and mid-IR spectrometer with no moving parts and no air path

The development of detector arrays and linear variable filters (LVF) with no moving parts and no exposed optical path is described. The resolution of the LVF is the prime determinant of spectral resolution and adding pixels will have little effect on spectral resolution. The variable filter array (VFA) spectrometer can be programmed so that a sample consisting of a correct blend of components in a process appears as a straight line on the spectrometer display. The VFA spectrometer can provide materials identification information and quantitative data and can supplement or replace the Fourier transform infrared (FTIR) spectrometer in many of its common usages.