Mantis shrimp-inspired organic photodetector for simultaneous hyperspectral and polarimetric imaging

Abstract

Combining hyperspectral and polarimetric imaging provides a powerful sensing modality with broad applications from astronomy to biology. Existing methods rely on temporal data acquisition or snapshot imaging of spatially separated detectors. These approaches incur fundamental artifacts that degrade imaging performance. To overcome these limitations, we present a stomatopod-inspired sensor capable of snapshot hyperspectral and polarization sensing in a single pixel. The design consists of stacking polarization-sensitive organic photovoltaics (P-OPVs) and polymer retarders. Multiple spectral and polarization channels are obtained by exploiting the P-OPVs' anisotropic response and the retarders' dispersion. We show that the design can sense 15 spectral channels over a 350-nanometer bandwidth. A detector is also experimentally demonstrated, which simultaneously registers four spectral channels and three polarization channels. The sensor showcases the myriad degrees of freedom offered by organic semiconductors that are not available in inorganics and heralds a fundamentally unexplored route for simultaneous spectral and polarimetric imaging.

Fig. 1. Mantis shrimp eye and bioinspired detector.

(A) Image of a mantis shrimp (O. Scyllarus). Photo credit: Michael Bok, Lund University. Representations of (B) the frontal view of the stomatopods eye, (C) bidirectional cross section of the rhabdom, (D) sagittal cross section of the midband (24, 57). Cells R1 to R8 are colored differently to distinguish their spectral sensitivity. (E) The structure of the SIMPOL sensor. Dashed arrows indicate the diattenuator’s transmission axis. (F) The folded retarder elements and the designed spectral retardance of each folded retarder.

Fig. 2. Spectral sensitivity of the detector.

(A) The modeled absorption spectra for four stacked OPV-FR pairs with nonideal OPV dichroism. a.u., arbitrary units. (B) The FWHM spectral resolution as a function of the number of retarders for each folded retarder. (C) The modeled absorption spectra for 15 stacked OPV-FR pairs with near-ideal OPV dichroism. (D) The measured transmission spectra of the fabricated FR filters.

Fig. 3. Organic photovoltaic details.

(A) Chemical structure of PBnDT-FTAZ and P(NDI2OD-T2). (B) An illustration of the rubbing procedure to orient the polymer semiconductor layer and (C) the layers of the semitransparent polarized OPV cell. (D) The absorbance anisotropy of the oriented PBnDT-FTAZ: P(NDI2OD-T2) film under linearly polarized light parallel (∥) and perpendicular (⊥) to the rubbing direction, and the resulting dichroic ratio. (E) Responsivity of P-OPV cell under linearly polarized light ∥ and ⊥ to the rubbing direction under 0-V bias.

Fig. 4. SIMPOL imaging setup and polarization imaging.

(A) Experimental setup of the SIMPOL single-pixel camera, (B) total intensity S₀, (C) S₁/S₀ reconstruction, (D) S₂/S₀ reconstruction, (E) DoLP, (F) AoP, and (G) perceptually uniform polarization-color mapping Viridis. Photo credit of target image: Colin, CC-BY-SA-4.0 (58). ND, neutral density filter; PH, pinhole.

Fig. 5. Combined spectral and polarization imaging.

Spectral images from (A) OPV3, (B) OPV4, (C) OPV5, and (D) OPV6. (E) Color composite from the OPV detectors and (F) color image combined with polarization image where polarization is represented by the arrows. The measured and SIMPOL reconstruction of the pencils spectra for (G) green, yellow, and red pencils and (H) cyan, blue, magenta, and orange pencils. Photo credit of target image: Colin, CC-BY-SA-4.0 (58).