Hyperspectral Imaging in Scattering Media using Two Filters

Abstract

Hyperspectral imaging is a common technique in fluorescence microscopy to obtain the emission spectrum at each pixel of an image. However, methods to obtain spectral resolution based on diffraction gratings or integrated prisms work poorly when the sample is strongly scattering. We developed a microscope named the DIVER that collects the fluorescence emission over a very large angle and sample area. We have shown that this microscope, depending on the tissue thickness, can capture several orders of magnitude more light than conventional microscopes using epi detection, which in turn significantly increases imaging depth. Since the fluorescence light after passing through the multiple scattering sample is not collimated, the use of grating or prisms strongly limits the amount of light that can be used with available hyperspectral devices. Here we show that two filters that accept uncollimated light over a large aperture are sufficient to calculate the spectral phasor rather than displaying the entire spectrum. Using the properties of the spectral phasors we can resolve spectral components and perform the type of data analyses that are usually performed in hyperspectral image analysis. (Supported in part by the NIH grant NIH P41-GM103540).