  We present a novel high-definition (HD) snapshot diffractive spectral imaging
system utilizing a diffractive filter array (DFA) to capture a single image
that encodes both spatial and spectral information. This single diffractogram
can be computationally reconstructed into a spectral image cube, providing a
high-resolution representation of the scene across 25 spectral channels in the
440-800 nm range at 1304x744 spatial pixels (~1 MP). This unique approach
offers numerous advantages including snapshot capture, a form of optical
compression, flexible offline reconstruction, the ability to select the
spectral basis after capture, and high light throughput due to the absence of
lossy filters. We demonstrate a 30-50 nm spectral resolution and compared our
reconstructed spectra against ground truth obtained by conventional
spectrometers. Proof-of-concept experiments in diverse applications including
biological tissue classification, food quality assessment, and simulated
stellar photometry validate our system's capability to perform robust and
accurate inference. These results establish the DFA-based imaging system as a
versatile and powerful tool for advancing scientific and industrial imaging
applications.
