Birefringent Fourier transform imaging spectrometer

We have previously shown those circumstances for which the multiplex advantage of temporally scanned Fourier transform imaging spectrometers enables higher signal-to-noise ratios than other techniques. Unfortunately, for many real-life applications, such as aerial reconnaissance, deployment of FT instruments based on traditional moving-mirror interferometers is problematic due to their inherent sensitivity to vibration. We will describe a new type of Fourier transform imaging spectrometer, employing moving birefringent prisms to create the necessary path difference modulations. This new system retains the accepted sensitivity advantages of traditional Fourier transform devices, but because it employs common-path interferometry and because path differences are introduced within a single optical element, the system is inherently very robust. Furthermore, the precision of the movement can be typically two orders of magnitude lower than for a traditional two-beam interferometer, resulting in a simpler instrument. Experimental results will be presented.