Hyperspectral Imaging Polarimetry
The overall goal of this proposal is to build and develop snapshot imaging spectropolarimeter that will be extremely convenient, and permit us to measure spectral and polarization information of the dynamic events with no moving or tunable parts by using the liquid crystal diffraction grating, polarization grating (PG).
Motivation for Approach
The spectral information is important to identify material properties while the polarization information is essential to determine the surface and shape of the objects. Measurements of the both spectral and polarization information are used in various fields including astronomy, remote sensing, and biomedical imaging/diagnosis. However, most systems are still specialized either for the spectrometry or polarimetry. The most recent technique for a simultaneous acquisition of both contents requires sequential detection using its moving parts or needs modulation process which leads to significant time consuming and reduces sampling resolution. Using the PGs, however, we can detect full spectral and polarization information on a two dimensional space without any moving parts or any modulation process. Since the spatially varying birefringence pattern of a PG leads to the imaging spectrum from the angular dispersion and polarization separation from the order of diffraction, the use of multiple PGs makes it possible to project spectral and polarization information with the two dimensional dispersion patterns. Moreover, some of the existing technologies cannot be applied for dynamic circumstance due to their lack of snapshot capability. Other systems can get a snapshot detection analyzing diffraction patterns which come from hologram disperser, but they lose the image resolution in Stokes spectra and are time consuming since they need a modulation process for extracting polarization information of the image. Our proposed imaging spectropolarimeter is uniquely compelling as it provides snapshot capability and polarization separation capability on the single detector. Comparing with other technologies, our new system has powerful potential for attaching to the conventional imaging systems due to the robust, compact and lightweight properties of our design.
This work are expected to further advance research in the imaging technology using optical elements. Our Polarization Grating Imaging Spectropolarimeter (PGIS), with a real-time image acquisition, would have major impact on all areas of life where there is a need for such technology, including Medical Imaging/Diagnosis, Biology, Military and so on.
Polarization Gratings (PGs)