Fig. 1. Large-area ultracompact pixelated aluminium wire-grid-based metamaterials for full-Stokes polarization imaging. (a) Schematic of the device design for Stokes parameters measurement. F1−F3 microcells are linear polarization filters to filter linearly polarized light with the electric field vector oriented at different angles with respect to the x axis, i.e., 0°, 45°, and 90°. F4 microcell is left circular polarization filter to transmit left circular polarization light. (b) Schematic of the linear polarization filters consisting of the double-layer wire-grid. The period, wire width, height, and spacing are P1, W1, H1, and D1, respectively. (c) Schematic of the left circular polarization filter consisting of a top circular–linear polarization converter and an underneath linear polarization filter. The period, wire width, height of the circular–linear polarization converter, and spacing between the circular–linear polarization converter and the linear polarization filter are P2, W3, H2, and D2, respectively.

Fig. 2. Optical parameters of the double-layer nano wire-grid linear polarization filter: (a) TM light transmission, (b) TE light transmission, and (c) linear polarization extinction ratio. Optical parameters of the single-layer nano wire-grid polarization filter: (d) TM light transmission, (e) TE light transmission, and (f) linear polarization extinction ratio. The geometric parameters of the wire-grid are 200 nm period and 100 nm wire width. The spacing between the bilayer wire grids D1=200  nm. Aluminium wire-grid height H1 varies from 10 to 90 nm.

Fig. 3. Simulated optical properties of circular polarization filter with diffrerent D2. (a), (b) Transmittance spectra of LCP and RCP by full-wave (400–1200 nm) simulation. (c), (d) Circular dichroism (CD=TLCP-TRCP) and circular polarization extinction ratio (CPER=TLCP/TRCP) obtained by the transmittance of LCP and RCP.

Fig. 4. Device fabrication. (a1) Preparation of IPS flexible template with 0°, 45°, 90°, and −45° orientation wire-grids. (a2) Formation of dielectric wire-grid on the quartz substrate precoated with UV-curable photoresist by UV-curable NIL. (a3) Aluminium wire-grid-based linear polarization filter micro arrays obtained by vertical thermal evaporation process. (b1) Preparation of large-area IPS flexible template with single-directional wire-grid. (b2) Aluminium wire-grid structure obtained by vertical thermal evaporation process. (c1) IPS surface metal nano wire-grid integrated onto the surface of the double-layer metal-aluminum nano wire-grid linear polarization filter micro array precoated with UV-curable photoresist by a nano transfer printing process. (c2) Spin-coating of BP212 on linear polarization filter micro array. (c3) Formation of pixelated metamaterials integrating both the linear polarization filters and circular polarization filters by photolithography, development, etching, and residual adhesive removal process.

Fig. 5. (a1), (a2) SEM surface views of IPS flexible template with 0°, 45°, 90°, and −45° orientation wire-grids. (b) SEM surface view of the UV-curable nanoimprint photoresist patterned with wire-grid structure. (c) SEM surface view of the aluminium nano wire-grids. (d) SEM surface view of the circular linear polarization converter. (e) Polarization micrograph of the prepared sample.

Fig. 6. (a) Experimental diagram of the fabricated device measurement system. (b) Example diagram of the imaging system imaging polarized light.

Fig. 7. (a), (c) Grayscale value response curves of the three F₁–F₃ linear polarization filter regions with different azimuthal angles of linear polarization light. (b), (d) Grayscale value response of the F₄ circular polarization filter with different chiral circularly polarized light. (a), (b) The filter operates at a wavelength of 810 nm. (c), (d) The filter operates at a wavelength of 740 nm.

Fig. 8. Testing results of Stokes parameters. The subplots in the left column represent the theoretical and calculated pre-calibration, post-calibration, and post-compensation values of the Stokes parameters S0−S3; the subplots in the right column represent the errors in the calculated pre-calibration, post-calibration, and post-compensation values of the Stokes parameters S0−S3.

Fig. 9. Polarimetric imaging. (a) Physical image and its corresponding original imaging and polarization state schematic. (b) Calculated Stokes parameter image. (c) Theoretical Stokes parameter image of the targeted polarization mask.