Polarization Multiplexed Metalens Array Optical Chip for High-Performance LWIR Polarimetric Camera

Abstract

Compared with traditional infrared thermal imaging, polarimetric imaging provides additional polarization information, which effectively enhances object contours and image contrast, with broad application in both military and civilian domains. However, the traditional long-wave infrared polarimetric camera suffers from severe thermal noise, low sensitivity and limited detection accuracy. To address the aforementioned problems, a novel cooled LWIR polarimetric camera based on an achromatic polarization multiplexed germanium-based metalens array optical chip is reported in this paper, enabling high-precision division of focal plane linearly polarimetric imaging. The proposed system demonstrates high-precision linearly polarimetric imaging, with the metalens array achieving an average transmittance of 84.7% across the 8.4~11.6{\mu}m band and a polarization extinction ratio exceeding 10. The metasurface-based camera attains an average polarization reconstruction error below 0.981%, markedly surpassing state-of-the-art commercial LWIR polarimetric systems. Additionally, the new camera presents excellent polarimetric imaging capability for complex scenes. To the best of our knowledge, this represents the world's first LWIR polarimetric camera utilizing the metasurface optical chip with performance superior to commercial cameras, promoting the practical development of metasurface-integrated devices.