Linear Variable Filters For Hyperspectral Imaging Applications

LASER COMPONENTS off ers linear variable fi lters, whereby either the centre wavelength of
a bandpass, or long/short pass edge increases along the length of a part. Each wavelength
is a function of position on the substrate. Spectral gradients of up to 80nm per mm can be
produced using hard oxide coatings, which have good environmental stability and are well
suited to both indoor and outdoor use.

For hyperspectral imaging applications, a linear variable fi lter is typically placed directly
over a sensor array or camera to provide spectral separation along an axis. Coupled with
the motion provided by either a drone or conveyer belt in the other axis, a “hypercube” of x,
y, z data can be produced. Our linear variable fi lters are a precision solution for hyperspec-
tral imaging, with full blocking of the out of band spectral range, high transmission in the
wavelengths of interest, and exceptional linearity across the filter

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