On-chip long-wavelength infrared polarimeter for full-Stokes polarization detection

Polarization detection is a critical technique in various research and application fields, especially in the long-wavelength infrared regime for target discrimination from complex backgrounds. With the trend of miniaturization and integration, on-chip full-Stokes polarimeters are eagerly pursued. However, how to achieve efficient linear and circular polarimetry simultaneously on the same detection material chip with sufficient polarization extinction ratios and responsivities still remains a challenge. In this work, we propose an on-chip long-wavelength infrared full-Stokes polarimeter based on the integration of anisotropic and twisted metamaterials on the same quantum well material chip. The device consists of six subpixels with different principle detection polarization states. Based on the dual polarization selection by the structure and the detection material, the linear polarization extinction ratio exceeds 10 ⁶ and the circular polarization extinction ratio reaches 150. In addition, the absorptance of the detection material is enhanced by more than 16 times. Through simple subtracting and normalization operations on the photocurrents of the subpixels, the Stokes parameters are obtained with small root mean square errors. The device performance remains at a high level over the incident angle range of ±5°. This work points out a promising way for on-chip long-wavelength infrared full-Stokes detection. The device architecture is compatible with focal plane arrays.