EAGER: High-performance Optical-phonon-based Terahertz Sources Operating at Room Temperature

EAGER：在室温下运行的基于光学声子的高性能太赫兹源

• 批准号: 1748518
• 负责人: Peter Qiang Liu
• 金额: $ 8.54万
• 依托单位: SUNY at Buffalo
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1748518&HistoricalAwards=false
• 关键词: EAGER; performance; Optical; phonon; based

Title: High-performance Optical-phonon-based Terahertz Sources Operating at Room TemperatureNon-technical DescriptionThe mid-infrared (MIR) to terahertz (THz) spectral range has its unique scientific and technological significance, as it hosts the strongest and fingerprint-like absorption lines of countless molecular species, making it the ideal spectral range for developing sensing technologies with superior selectivity and sensitivity for a broad range of applications. Quantum cascade lasers (QCLs) are currently the preferred light sources for many applications in this spectral range, thanks to their compactness, convenient operation and high output power. However, in the THz region the performance of QCLs is still not sufficient for various real-world applications. THz QCLs have much lower performance than MIR QCLs, and the highest operating temperature of THz QCLs is still limited to ~200K. Furthermore, currently no QCL can operate within the 5 THz to 11THz range. In this exploratory project, we plan to develop a new type of compact, high-performance and room-temperature operating THz sources to cover this "gap" spectral range. The proposed devices are based on an untested but promising new operation principle, and the successful demonstration of such devices will bring transformative impacts to the research field of THz sources and enable various applications. Therefore, the proposed research is suitable for the NSF EAGER program. This project will allow graduate and undergraduate students to actively participate in cutting-edge research, and acquire the knowledge, skills, experiences and broad perspectives necessary for their future leadership in scientific research and technology development on the competitive global stage. Combining research with education and outreach activities will also be a focus of our work, aiming at benefiting students of all age-groups and backgrounds, including those from underrepresented groups.Technical DescriptionThe objective of this project is to systematically explore how to realize a new type of THz sources based on a fundamentally different device operation principle. The device operation principle consists of two key processes: (1) generating optical phonons by resonant inter-subband transitions in multiple-quantum-wells (MQWs), and (2) transferring the energy from the generated optical phonons to resonant THz antennae which then emit photons into free space. As the device operation principle is not sensitive to temperature, such THz sources should operate well at room temperature and above. Designs of the MQWs and the THz antennae will be optimized to make both processes efficient, leading to a high overall energy conversion efficiency which is potentially orders of magnitude higher than that of typical THz QCLs. Moreover, such THz sources have a surface-emitting configuration, so the output power scales up with the device area. The proposed research may also allow us to gain new and/or deeper insights into the interesting and complex physics underlying the interplay between inter-subband transitions in MQWs, optical phonons and electromagnetic resonances of photonic structures. Interactions involving all three excitations have not been systematically studied. A better understanding of the underlying physics will guide us to improve the device design, and may inspire us to pursue new possibilities of more advanced devices.

标题：室温下运行的高性能基于光学声子的太赫兹源非技术性描述中红外（MIR）至太赫兹（THz）光谱范围具有其独特的科学和技术意义，因为它具有最强的指纹状吸收无数分子种类的谱线，使其成为开发传感技术的理想光谱范围，具有卓越的选择性和灵敏度，适用于广泛的应用。量子级联激光器 (QCL) 目前是该光谱范围内许多应用的首选光源，因为它们结构紧凑、操作方便且输出功率高。然而，在太赫兹区域，QCL 的性能仍然不足以满足各种实际应用的需要。太赫兹 QCL 的性能远低于 MIR QCL，并且太赫兹 QCL 的最高工作温度仍限制在 ~200K。此外，目前还没有 QCL 可以在 5 THz 至 11 THz 范围内工作。在这个探索性项目中，我们计划开发一种新型紧凑型、高性能、室温操作的太赫兹源，以覆盖这个“间隙”光谱范围。所提出的设备基于未经测试但有前途的新工作原理，此类设备的成功演示将为太赫兹源的研究领域带来变革性影响并实现各种应用。因此，本研究适合 NSF EAGER 计划。该项目将使研究生和本科生积极参与前沿研究，并获得未来在竞争激烈的全球舞台上领导科学研究和技术开发所需的知识、技能、经验和广阔的视野。将研究与教育和推广活动相结合也将是我们工作的重点，旨在使所有年龄段和背景的学生受益，包括来自代表性不足群体的学生。技术描述该项目的目标是系统地探索如何实现一种新型基于根本不同的设备操作原理的太赫兹源。该器件的工作原理包括两个关键过程：(1) 通过多量子阱 (MQW) 中的谐振子带间跃迁生成光学声子，(2) 将生成的光学声子的能量转移到谐振太赫兹天线，然后将光子发射到自由空间。由于器件工作原理对温度不敏感，此类太赫兹源应在室温及以上温度下良好工作。 MQW 和太赫兹天线的设计将进行优化，以使这两个过程高效，从而实现较高的整体能量转换效率，这可能比典型的太赫兹 QCL 高出几个数量级。此外，这种太赫兹源具有表面发射配置，因此输出功率随着器件面积的增加而增加。拟议的研究还可以让我们获得新的和/或更深入的见解，了解量子阱中子带间跃迁、光学声子和光子结构的电磁共振之间相互作用的有趣和复杂的物理现象。涉及所有三种激发的相互作用尚未得到系统研究。对底层物理的更好理解将指导我们改进设备设计，并可能激励我们追求更先进设备的新可能性。