1. Achieving Ultra‐High Background‐Limited Detectivity by a Brillouin Zone Folding Induced Quasi‐Bound State in the Continuum.
- Author
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Zhu, Tianyun, Jing, Wenji, Deng, Jie, Wang, Bo, Wang, Ruowen, Ye, Tao, Shi, Mengdie, Ye, Jiexian, Cui, Tianyuan, Shen, Jinyong, Li, Fangzhe, Ning, Jun, Zhou, Jing, and Chen, Xiaoshuang
- Subjects
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QUALITY factor , *BRILLOUIN zones , *BACKGROUND radiation , *HEAT radiation & absorption , *PHOTODETECTORS , *INFRARED detectors - Abstract
During infrared detection, the thermal radiation from the background generates substantial photon noise and thus severely limit the capability of an infrared detector to identify a target. Going beyond this limitation has been a long‐standing challenge in the development of infrared detectors. This paper proposes to break this limitation by creating a narrow photoresponse band with a high peak responsivity to reject the background radiation and enhance the responsivity to the target with characteristic emission lines. This scheme is numerically demonstrated in a dimerized grating integrated quantum well infrared photodetector, based on critical coupling with a Brillouin zone folding induced quasi‐bound state in the continuum (BIC). The asymmetric deformation of the grating structure folds the photonic band and generates a quasi‐BIC with a tunable high radiation Q factor (QR) at the Γ point. By reducing the doping concentration of the quantum wells for a high absorption Q factor (QA) and tuning the QR to make QR = QA for critical coupling, a narrowband photoresponse with a high peak responsivity is achieved and the background‐limited specific detectivity of 4.55 × 1012 cm Hz1/2 W−1 is obtained for a 2π field of view, surpassing the ideal‐photoconductor limit by 92 times. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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