Geometric Filterless Photodetectors for Mid-infrared Spin Light

• Published in: arXiv.org
• Main Authors: Wei, Jingxuan, Chen, Yang, Li, Ying, Li, Wei, Xie, Junsheng, Lee, Chengkuo, Novoselov, Kostya S, Cheng-Wei, Qiu
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 08.04.2022
• Subjects: Circular polarization; Discrimination; Ellipticity; Graphene; Infrared radiation; Optoelectronic devices; Photometers; Physics - Applied Physics; Physics - Optics; Polarized light; Polarizers; Room temperature
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2204.03980

Free-space circularly polarized light (CPL) detection, requiring polarizers and waveplates, has been well established, while such spatial degree of freedom is unfortunately absent in integrated on-chip optoelectronics. So far, those reported filterless CPL photodetectors suffer from the intrinsic small discrimination ratio, vulnerability to the non-CPL field components, and low responsivity. Here, we report a distinct paradigm of geometric photodetectors in mid-infrared exhibiting colossal discrimination ratio, close-to-perfect CPL-specific response, a zero-bias responsivity of 392 V/W at room temperature, and a detectivity of ellipticity down to 0.03\(^o\) Hz\(^{-1/2}\). Our approach employs plasmonic nanostructures array with judiciously designed symmetry, assisted by graphene ribbons to electrically read their near-field optical information. This geometry-empowered recipe for infrared photodetectors provides a robust, direct, strict, and high-quality solution to on-chip filterless CPL detection and unlocks new opportunities for integrated functional optoelectronic devices.