Mid-infrared semimetal polarization detectors with configurable polarity transition

• Published in: Nature photonics Vol. 15; no. 8; pp. 614 - 621
• Main Authors: Wei, Jingxuan, Xu, Cheng, Dong, Bowei, Qiu, Cheng-Wei, Lee, Chengkuo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2021; Nature Publishing Group
• Subjects: 142/126; 639/301/357/918; 639/624/1075/1082; 639/624/1075/401; 639/624/1107/510; 639/624/400/1021; Applied and Technical Physics; Design; Graphene; Infrared detectors; Light; Metalloids; Perturbation; Photometers; Photonics; Photoresponse; Physics; Physics and Astronomy; Polarity; Polarization; Quantum Physics; Semiconductors; Sensors; Transistors; Transition points; Tuning; Values
• ISSN: 1749-4885; 1749-4893
• DOI: 10.1038/s41566-021-00819-6

On-chip polarization-sensitive photodetectors offer unique opportunities for next-generation ultra-compact polarimeters. So far, mainstream approaches have relied on the anisotropic absorption of natural materials or artificial structures. However, such a model is inherently restricted by correlation between the polarization ratio (PR) and diattenuation, leading to small PR values (1 < PR < 10). Here, we report nanoantenna-mediated semimetal photodetectors, which enable configurable polarity transition by exploiting the vectorial and non-local photoresponse in semimetals. By tuning the orientation of nanoantennas, PR values vary from positive (unipolar regime) to negative (bipolar regime), covering all possible numbers (1 → ∞/−∞ → −1). In particular, the PR values at the polarity-transition point could approach infinity. Such a polarity transition hereby transcends the conventional PR–diattenuation relationship. Furthermore, our device allows the subtle measurement of polarization-angle perturbation down to 0.02° Hz −1/2 in the mid-infrared range. Our findings highlight the potential of semimetals as a promising material platform for miniaturized polarimetry. Mid-infrared polarization detectors based on nanoantenna-mediated few-layer graphene are demonstrated. By tuning the orientation of nanoantennas, the polarization ratios vary from positive to negative, and cover values from 1 to ∞/−∞ then to −1.