High-Temperature Terahertz Quantum Cascade Lasers

0500925 Hu拟议的研究旨在开发在高温下工作的太赫兹量子级联激光器（THz QCL）。具体来说，到拟议的三年期结束时，首席研究员设想开发可以在200 K以上温度下工作的THz QCL，以便它们可以方便地通过热电冷却器冷却。这种发展将对太赫兹频率的科学和技术产生重大影响，其潜在应用在化学和生物制剂的检测、医疗和安全应用的成像、天体物理学、等离子体诊断、远程大气传感和监测、高带宽自由空间通信和超高速信号处理等方面都是有希望的。该项目具有高度挑战性，因为在200 K时，热能大于光子能量，频率低于4.2 THz。为了实现这一目标，PI已经确定在高温下保持粒子数反转是关键问题。在全面分析的基础上，PI制定了一项战略，以系统地解决这一问题。 拟议活动的知识价值： 该项目将涉及大量的设计工作，因为量子威尔斯的数量将很大，它们的组合可能会很复杂。如果孤立量子阱可以看作是一维的“人造原子”，那么多量子阱（MQW）结构就是“人造分子”。这个项目就是设计和制造这样的人造分子，以实现太赫兹激光器的预期功能。首席研究员在该领域拥有最好的记录之一，可以使用开展研究活动所需的所有设施。拟议活动产生的更广泛影响：在最近的突破之后，主要研究者应邀在许多著名会议上发表特邀/全体/主旨演讲。这项工作也被广泛的社区媒体报道，如技术评论和NPR市场。通过合作，PI小组开发的THz激光器通过增加一个关键的使能组件，帮助加强了其他机构在THz相关活动中的基础设施。 首席研究员已将研究项目中的元素纳入固态物理研究生课程和本科核心课程信号与系统。他计划在项目期间进一步整合教学和研究。此外，已经并将继续努力让代表性不足的群体和本科生参与研究活动。

0500925Hu The proposed research seeks to develop terahertz quantum-cascade lasers (THz QCLs) that operate at high temperatures. Specifically, by end of the proposed three-year period, the principal investigator envisions the development of THz QCLs that can operate at temperatures above 200 K, so that they can be conveniently cooled by thermoelectric coolers. Such a development will have a significant impact on the science and technologies in THz frequencies, where potential applications are promising in detection of chemical and biological agents, imaging for medical and security applications, astrophysics, plasma diagnostics, remote atmospheric sensing and monitoring, high-bandwidth free-space communications, and ultrahigh-speed signal processing. This project is highly challenging, since at 200 K, the thermal energy is greater than the photon energy, , at frequencies below 4.2 THz. Towards this goal, the PI has identified that maintaining population inversion at high temperatures is the key issue. Based on a thorough analysis, the PI has developed a strategy to systematically address this issue. Intellectual merit of the proposed activity: The project will involve a considerable amount of design effort, as the number of quantum wells will be large and their combination will likely be complicated. If an isolated quantum well can be viewed as a one-dimensional "artificial atom", then a multiple quantum-well (MQW) structure is an "artificial molecule". This project is nothing short of designing and making such artificial molecules that perform the desired function of THz lasers. The principal investigator has one of the best track records in the field and has access to all the necessary facilities to carry out the research activities. Broader impacts resulting from the proposed activity: Following the recent breakthrough, the principal investigator has been invited to give invited/plenary/keynote talks at many prestigious conferences. The work has also been reported in media for broad communities such as Technology Review and NPR Market Place. Through collaborations, the THz lasers developed in the PI's group have helped to enhance infrastructures at other institutions in THz-related activities by adding a crucial enabling component. The principal investigator has incorporated elements in the research project into a graduate course in solid-state physics and a undergraduate core course Signals and Systems. He plans to further this integration of teaching and research during the project. Furthermore, effort has been made and will be continuingly made to involve members from underrepresented groups and undergraduate students in the research activities.