Fast thermal relaxation in cavity-coupled graphene bolometers with a Johnson noise read-out
Fast thermal relaxation in cavity-coupled graphene bolometers with a Johnson noise read-out
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DOI：
10.1038/s41565-018-0169-0
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发表时间：
2018-09-01
影响因子：
38.3
通讯作者：
Englund, Dirk
中科院分区：
文献类型：
--
作者：
Efetov, Dmitri K.;Shiue, Ren-Jye;Englund, Dirk
高灵敏度、快速响应时间和强光吸收是红外传感和成像的重要指标。这些特性之间的权衡仍然是测辐射热学的主要挑战。石墨烯具有创纪录的小电子热容和微弱的电子-声子耦合的独特组合，已成为一种允许高本征带宽的灵敏测辐射热介质1-3。此外，通过集成到光子结构中，该材料的光吸收可以增强到接近统一。在这里，我们介绍了一种基于约翰逊噪声读出超净六方氮化硼石墨烯中电子的集成热电子测辐射热计，该石墨烯通过Q=900的光子纳米腔与入射辐射进行临界耦合。该设备工作在电信波长，并在电荷中性条件下显示出增强的测辐射响应。在5K下，我们获得了约10PW HZ(-1/2)的噪声等效功率，创纪录的快速热弛豫时间，<；35ps，以及改善的光吸收。然而，该设备甚至可以在300K以上工作，但灵敏度降低。研究了石墨烯测辐射热计的性能、机理和局限性，为石墨烯测辐射热计的实际应用发展提供了重要的启示。
High sensitivity, fast response time and strong light absorption are the most important metrics for infrared sensing and imaging. The trade-off between these characteristics remains the primary challenge in bolometry. Graphene with its unique combination of a record small electronic heat capacity and a weak electron-phonon coupling has emerged as a sensitive bolometric medium that allows for high intrinsic bandwidths1-3. Moreover, the material's light absorption can be enhanced to near unity by integration into photonic structures. Here, we introduce an integrated hot-electron bolometer based on Johnson noise readout of electrons in ultra-clean hexagonal-boron-nitride-encapsulated graphene, which is critically coupled to incident radiation through a photonic nanocavity with Q = 900. The device operates at telecom wavelengths and shows an enhanced bolometric response at charge neutrality. At 5 K, we obtain a noise equivalent power of about 10 pW Hz(-1/2), a record fast thermal relaxation time, < 35 ps, and an improved light absorption. However the device can operate even above 300 K with reduced sensitivity. We work out the performance mechanisms and limits of the graphene bolometer and give important insights towards the potential development of practical applications.