MetaSpectra+: A Compact Broadband Metasurface Camera for Snapshot Hyperspectral+ Imaging

Abstract

We present MetaSpectra+, a compact multifunctional camera that supports two operating modes: (1) snapshot HDR + hyperspectral or (2) snapshot polarization + hyperspectral imaging. It utilizes a novel metasurface-refractive assembly that splits the incident beam into multiple channels and independently controls each channel's dispersion, exposure, and polarization. Unlike prior multifunctional metasurface imagers restricted to narrow (10-100 nm) bands, MetaSpectra+ operates over nearly the entire visible spectrum (250 nm). Relative to snapshot hyperspectral imagers, it achieves the shortest total track length and the highest reconstruction accuracy on benchmark datasets. The demonstrated prototype reconstructs high-quality hyperspectral datacubes and either an HDR image or two orthogonal polarization channels from a single snapshot.

Figures (12)

• Figure 1: Overview. (a) MetaSpectra+ employs a compact, hybrid optical assembly that integrates refractive lenses with metasurfaces (blue), forming multiple images in a single shot, each engineered with distinct dispersion, exposure, or polarization. The system reconstructs a hyperspectral datacube together with either an HDR image or two polarization channels from a snapshot capture. (b) Compared with previous multifunctional metasurface systems khorasaninejad2016multispectralguo2019compacthazineh2023polarizationbrookshire2024metahdrliu2025metah2, the hybrid optical design of MetaSpectra+ supports a significantly broader operating bandwidth and a lower F-number, while being comparably compact.
• Figure 2: MetaSpectra+ optical design. The optical assembly simultaneously captures multiple sub-images $I_{1:V}$ of the same scene from broadband illumination, each with independently controlled dispersion, exposure, and polarization sensitivity, using a compact two-layer metasurface design.
• Figure 3: MetaSpectra+ prototype. (a) Photograph of the experimental setup. The metasurfaces (MS), lenses, filters, and photosensors are mounted on a combination of commercial opto-mechanical components and custom 3D-printed holders. Additional implementation details are provided in the supplement. (b) Sample SEM image of the metasurfaces used in the system. The devices employ a SiN nanocylinder array for phase and dispersion control; the inset illustrates the nanocell parametrization. (c) Representative raw measurements. Sub-images $I_1$ and $I_2$ exhibit orthogonal dispersion, while $I_3$ and $I_4$ remain achromatic. A picture of the target is included in the supplement. Zoom in for fine details. (d) Calibrated spectral responses $\alpha_{1:4}(\lambda)$. The varied peak wavelengths are due to the different design wavelengths $\lambda_c$ for each sub-image. (e) Measured point spread functions across wavelengths. The PSFs for $I_1$ and $I_2$ show wavelength-dependent lateral shifts with consistent focus, whereas those for $I_3$ and $I_4$ remain spatially stationary, confirming their achromatic behavior.
• Figure 4: Sample hyperspectral reconstruction results on the KAUST dataset. MetaSpectra+ produces the highest structural fidelity and spectral accuracy among all compared methods. See enlarged insets for details. The inset numbers are PSNR (dB) for hyperspectral reconstructions.
• Figure 5: Sample real-world results of MetaSpectra+. (a) Hyperspectral imaging only. (b) HDR + hyperspectral imaging. Inset numbers represent the dynamic range (dB) of the picture. Compared to low-dynamic range (LDR) images recorded with CMOS cameras, the reconstructed HDR images from MetaSpectra+ demonstrate increases of 11 dB in dynamic range, and preserve both dark and bright scene details. Zoom in for finer structures. Inset numbers represent the dynamic range (dB) of the scene. (c) Polarization + hyperspectral imaging. The sample scene includes a $0^\circ$ linear polarizer, which appears dark in $I_4$ since this sub-image measures the $90^\circ$ polarization component.