Collaborative Research: Wavelength-Scalable, Room-Temperature Mid-Infrared Photodetectors Based on Multiphoton-Assisted Tunneling

题目：合作研究：基于多光子辅助隧道的波长可扩展室温中红外探测器中红外（MIR）电磁辐射探测在基础科学和应用技术中都具有重要意义。它的广泛应用范围从自由空间通信、夜视、无损检测、环境监测、医学诊断、光谱学和天文学研究，到生物分子和化学信号的敏感检测。然而，目前基于窄带隙半导体的MIR光电探测器通常有几个固有的缺点，如响应时间慢、成本高、灵敏度低，最关键的是，需要低温冷却，这实际上阻碍了它们的便携式应用。这项合作研究旨在研究一种新的MIR探测机制，该机制基于量子力学现象，即纳米级金属-绝缘体-金属结构中的多光子辅助隧道效应，从而开发出新的等离子体-电子MIR探测器，实现超快速、高效、无冷却和波长可扩展的光探测。这个跨学科的研究结合了量子力学、光子学、电磁学、纳米技术和纳米材料，将为研究生、本科生和K-12学生提供独特的多学科研究经验。该项目通过一系列活动，如“女性参与工程项目”和“早期研究学者项目”，将研究、教育和社区外展工作紧密结合起来，以增加女性和未被充分代表的少数族裔在STEM领域的代表性。这项合作研究的目的是开发新的等离子体电子纳米器件，它可以丰富量子领域等离子体的功能组合，并可以导致超快，高效，室温和波长可扩展的中红外（MIR）光电探测器。我们将使用创新的纳米光子和纳米材料技术来显著提高发生在金属-绝缘体-金属（MIM）等离子体异质结构中的多光子辅助隧道（MPAT）过程的光子到电子转换效率。我们将首先理论建模，实验表征，并充分阐明在MIR和长波长体制下与MPAT相关的光学整流效应。然后，我们将介绍(1)新型的光学纳米天线和基于MIM的光学超表面，以提高光在MIM隧道纳米结中的耦合效率和定位；(2)一类新的二维（2D）过渡金属氧化物（TMO）作为可控的、超高质量的原子尺度隧道势垒。在这些等离子电子MIR光电探测器中，由光学纳米天线或加载二维TMO隧道势垒的超表面结构组成的隧道等离子激元诱导的强光学非线性和等离子体增强的场局域化可能使最先进的光转换量子产量成为可能。从这项研究中获得的知识将有助于建立一个新的范例，用于在非线性量子体制下使用等离子体器件检测和收集红外辐射，并将揭示其他等离子体增强的MPAT过程，如红外体制下的高谐波产生、非线性波混频和双光子吸收。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Title: Collaborative Research: Wavelength-Scalable, Room-Temperature Mid-Infrared Photodetectors Based on Multiphoton-Assisted TunnelingDetection of mid-infrared (MIR) electromagnetic radiation is of central importance in both fundamental sciences and applied technologies. It finds widespread applications ranging from free-space communication, night vision, nondestructive testing, environmental monitoring, medical diagnostics, spectroscopy, and astronomy research, to the sensitive detection of biomolecular and chemical signals. However, current MIR photodetectors based on narrow-bandgap semiconductors typically suffer from several inherent drawbacks, such as slow response time, high cost, low sensitivity, and most critically, the need for cryogenic cooling that practically prohibits them from portable applications. This collaborative research aims to study a new MIR detection mechanism based on a quantum mechanical phenomenon referred to as multiphoton-assisted tunneling in nanoscale metal–insulator–metal structures toward the development of new plasmo-electronic MIR detectors, which enable ultrafast, efficient, cooling-free, and wavelength-scalable photodetection. This interdisciplinary research interfacing quantum mechanics, photonics, electromagnetics, nanotechnologies, and nanomaterials will provide graduate, undergraduate, and K-12 students with unique multidisciplinary research experiences. The project tightly integrates research, education and community outreach efforts through a series of activities, such as Women in Engineering Program and Early Research Scholars Program, to increase the representation of women and underrepresented minorities in the STEM fields.This collaborative research aims to develop fundamentally new plasmo-electronic nanodevices, which can enrich the functional portfolio of plasmonics in the quantum domain and can lead to ultrafast, highly-efficient, room-temperature, and wavelength-scalable mid-infrared (MIR) photodetectors. We will use innovative nanophotonic and nanomaterial techniques to significantly improve the photon-to-electron conversion efficiency of the multiphoton-assisted tunneling (MPAT) processes occurring in metal–insulator–metal (MIM) plasmonic heterostructures. We will first theoretically model, experimentally characterize, and fully elucidate the optical rectification effect associated with MPAT in the MIR and long-wavelength regimes. Then, we will introduce (1) novel optical nanoantennas and MIM-based optical metasurfaces to enhance the coupling efficiency and localization of light into the MIM tunneling nanojunction, and (2) a new class of two-dimensional (2D) transition metal oxides (TMO) serving as controllable, ultrahigh-quality atomic-scale tunnel barriers. The strong optical nonlinearities induced by tunneling plasmons and the plasmonically-enhanced field localization in these plasmo-electronic MIR photodetectors, consisting of optical nanoantenna or metasurface structures loaded with the 2D TMO tunnel barrier, may enable the state-of-the-art photoconversion quantum yields. The knowledge gained from this research will help establish a new paradigm for detecting and harvesting infrared radiation using plasmonic devices operated in the nonlinear quantum regime, and will shed light on other plasmonically-enhanced MPAT processes, such as high harmonic generation, nonlinear wave mixing, and two-photon absorption, in the infrared regime.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.