Hot electrons generated in metallic nanostructures have shown promising perspectives for photodetection. This has prompted efforts to enhance the absorption of photons by metals. However, most strategies require fine-tuning of the geometric parameters to achieve perfect absorption, accompanied by the demanding fabrications. Here, we theoretically propose a Ag grating/TiO 2 cladding hybrid structure for hot electron photodetection (HEPD) by combining quasi-bound states in the continuum (BIC) and plasmonic hot electrons. Enabled by quasi-BIC, perfect absorption can be readily achieved and it is robust against the change of several structural parameters due to the topological nature of BIC. Also, we show that the guided mode can be folded into the light cone by introducing a disturbance to become a guided resonance, which then gives rise to a narrow-band HEPD that is difficult to be achieved in the high loss gold plasmonics. Combining the quasi-BIC and the guided resonance, we also realize a multiband HEPD with near-perfect absorption. Our work suggests new routes to enhance the light-harvesting in plasmonic nanosystems.

中文翻译：

---

在连续介质和引导共振中具有准束缚态的等离子体热电子光电探测

在金属纳米结构中产生的热电子显示出用于光电检测的前景。这促使人们努力提高金属对光子的吸收。然而，大多数策略需要微调几何参数以实现完美的吸收，同时伴随着苛刻的制造。在这里，我们从理论上提出了一种用于热电子光电探测 (HEPD) 的 Ag 光栅/TiO 2 包覆混合结构，通过将连续介质中的准束缚态 (BIC) 和等离子体热电子相结合。通过准 BIC，可以很容易地实现完美的吸收，并且由于 BIC 的拓扑性质，它可以抵抗几个结构参数的变化。此外，我们还表明，通过引入扰动成为引导共振，可以将导模折叠到光锥中，然后产生在高损耗金等离子体中难以实现的窄带 HEPD。结合准 BIC 和引导共振，我们还实现了具有近乎完美吸收的多波段 HEPD。我们的工作提出了增强等离子体纳米系统中光捕获的新途径。