Lensless efficient snapshot hyperspectral imaging using dynamic phase modulation

Snapshot hyperspectral imaging based on a diffractive optical element (DOE) is increasingly featured in recent progress in deep optics. Despite remarkable advances in spatial and spectral resolutions, the limitations of current photolithography technology have prevented the fabricated DOE from being designed at ideal heights and with high diffraction efficiency, diminishing the effectiveness of coded imaging and reconstruction accuracy in some bands. Here, we propose, to our knowledge, a new lensless efficient snapshot hyperspectral imaging (LESHI) system that utilizes a liquid-crystal-on-silicon spatial light modulator (LCoS-SLM) to replace the traditionally fabricated DOE, resulting in high modulation levels and reconstruction accuracy. Beyond the single-lens imaging model, the system can leverage the switch ability of LCoS-SLM to implement distributed diffractive optics (DDO) imaging and enhance diffraction efficiency across the full visible spectrum. Using the proposed method, we develop a proof-of-concept prototype with an image resolution of 1920 × 1080 pixels, an effective spatial resolution of 41.74 μm, and a spectral resolution of 10 nm, while improving the average diffraction efficiency from 0.75 to 0.91 over the visible wavelength range (400–700 nm). Additionally, LESHI allows the focal length to be adjusted from 50 mm to 100 mm without the need for additional optical components, providing a cost-effective and time-saving solution for real-time on-site debugging. LESHI is the first imaging modality, to the best of our knowledge, to use dynamic diffractive optics and snapshot hyperspectral imaging, offering a completely new approach to computational spectral imaging and deep optics.