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Optical Chirality Detection Using a Topological Insulator Transistor

Optical chirality is an effective means in screening molecules and their enantiomers in bioengineering, and recently has garnered attention as an implementation of qubits in quantum information processing. The conventional detection of circularly polarized light (CPL) is based on phase retardation a...

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Bibliographic Details
Published in:Advanced optical materials 2021-05, Vol.9 (10), p.n/a
Main Authors: Huang, Shouyuan, Xu, Xianfan
Format: Article
Language:English
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Summary:Optical chirality is an effective means in screening molecules and their enantiomers in bioengineering, and recently has garnered attention as an implementation of qubits in quantum information processing. The conventional detection of circularly polarized light (CPL) is based on phase retardation and polarization separation using multiple optical components. An intrinsic solid‐state chirality detection device would be favorable for easier integration and implementation. Optical spin injection to the spin‐momentum‐locked topological surface states of topological insulators (TIs) by circularly polarized light leads to a directional DC photocurrent and hence possible circular polarization detection. However, this DC photocurrent is also accompanied by other photo‐responses. Here, a photodetection strategy using a TI transistor which senses CPL without the use of any additional components is demonstrated, it achieves a uniform response over the entire device with a sensitivity ≈5.6%. The Stokes parameters can also be extracted by arithmetic operation of photocurrents obtained with different bias and gate for a complete characterization of a polarized light beam. Therefore, this method enables chirality detection and Stokes parameter analysis using a single device. The proposed miniaturized intrinsic chirality detectors facilitate polarimetry sensing in applications from circular dichroism spectroscopy to biomedical diagnosis. Conventional optical chirality detection requires the use of multiple optical components. Here, a topological insulator‐based phototransistor for chirality detection is reported. The helical photoconductivity responds solely to the chirality of circularly polarized light and hence is used for sensing. In addition, all Stokes parameters can be extracted from photocurrents by applying different biases and gate voltages.
ISSN:2195-1071
2195-1071
DOI:10.1002/adom.202002210