Ultraspectral Imaging and the Snapshot Advantage

Ultraspectral sensing has been investigated as a way to resolve terrestrial chemical fluorescence within solar Fraunhofer lines. Referred to as Fraunhofer Line Discriminators (FLDs), these sensors attempt to measure “band filling” of terrestrial fluorescence within these naturally dark regions of the spectrum. However, the method has challenging signal to noise ratio limitations due to the low fluorescence emission signal of the target, which is exacerbated by the high spectral resolution required by the sensor (<0.1 nm). To now, many Fraunhofer line discriminators have been scanning sensors; either pushbroom or whiskbroom, which require temporal and/or spatial scanning to acquire an image. In this paper, we attempt to quantify the snapshot throughput advantage in ultraspectral imaging for FLD. This is followed by preliminary results of our snapshot FLD sensor. The system has a spatial resolution of 280×280 pixels and a spectral resolving power of approximately 10,000 at a 658 nm operating wavelength.