Collaborative research: Compact room temperature operated THz emitters with scalable architecture and low electric power consumption

摘要标题：非技术性：太赫兹传感是一种非侵入性的生物和化学危险物质检测、癌症检测、地雷和爆炸物检测、建筑物、机场和其他公共场所的安全检查，以及在大气中的太赫兹传输窗口进行短距离隐蔽通信的技术。目前可用的太赫兹源要么体积庞大，要么需要低温冷却，导致高成本、高复杂性和通常低可靠性。所提出的新颖设计概念旨在解决当前最先进的太赫兹发射器技术的大多数缺陷。目标器件的实现在复杂性、可靠性和尺寸方面与广泛使用的标准廉价近红外二极管激光器相似。这项工作的成功将使太赫兹成像和光谱传感器在安全检查、医疗诊断和工业监控应用中得到广泛部署。该项目需要在理论和实验之间进行密切相关的努力，包括广泛的建模，器件制造方法的优化以及新型激光发射器的详细表征和现场测试。研究工作与教育和推广计划相结合，旨在增加纽约和得克萨斯州公立大学和当地社区的教育机会。技术：该项目的主要目标是开发具有内置谐振非线性的高功率二极管激光器，用于在太赫兹光谱范围内高效产生腔内差频。基于非对称耦合量子威尔斯阱的增益部分利用了可以在锑化物材料系统中实现的独特能带对准。在2微米附近的两个紧密间隔的波长处产生的激光模式将用作差频产生的腔内泵浦场。在该光谱区域中发射的锑化物基二极管激光器展示了半导体激光器有史以来实现的最低阈值电流密度、优异的温度稳定性和瓦级输出功率，所有这些都在室温下实现。所提出的具有微到毫瓦太赫兹输出水平的设备操作所需的预期电功率输入将比现有技术低两到三个数量级。拟议的研究提供了实验和理论研究的基本问题，在锑化物为基础的量子阱系统的谐振光学非线性在广泛的载流子种群从非简并到高度简并。所提出的器件的未来发展将包括广泛可调谐太赫兹发射器的制造以及与硅光子学的集成。将该技术转移到砷化物或硅平台将使太赫兹发射器的大面积阵列的外延侧向下安装能够将输出太赫兹功率放大到数十毫瓦级并执行太赫兹光束整形。

Abstract Title: Compact and efficient room temperature operated terahertz emitters for industrial, medical and home security applications.Nontechnical:Terahertz sensing is an enabling technology for noninvasive detection of biological and chemical hazardous agents, cancer detection, detection of mines and explosives, security screening in buildings, airports, and other public space, as well as short-range covert communications in terahertz transmission windows of the atmosphere. Currently available terahertz sources are either bulky or require cryogenic cooling leading to high costs, high complexity, and often low reliability. The proposed novel design concept aims to address most of the deficiencies of the current state-of-the-art terahertz emitter technology. The target device implementation will be similar in terms of the complexity, reliability and size to widely used standard inexpensive near infrared diode lasers. The success of the proposed effort will enable wide deployment of terahertz imaging and spectroscopic sensors for the security screening, medical diagnostics, and industrial monitoring applications. The project requires strongly correlated effort between theory and experiment including extensive modeling, optimization of the device fabrication methodologies as well as detailed characterization and field testing of the novel laser emitters. The research effort is integrated with educational and outreach plans aimed at enhancing education opportunities at the New York and Texas public universities and local communities. Technical:The main goal of the project is the development of high-power diode lasers with built-in resonant nonlinearity for efficient intra-cavity difference frequency generation in the terahertz spectral range. The gain sections based on asymmetric coupled quantum wells utilize the unique band alignment that can be realized in an antimonide material system. Laser modes generated at two closely spaced wavelengths near 2 microns will serve as an intracavity pump field for difference frequency generation. The antimonide-based diode lasers emitting in that spectral region demonstrate some of the lowest threshold current densities ever achieved for semiconductor lasers, excellent temperature stability, and watt level output power, all at room temperature. The expected electrical power input necessary for the proposed device operation with micro to milliwatt terahertz output level will be two to three orders of magnitude lower than those of existing technologies. The proposed research offers experimental and theoretical studies of the fundamental problem of resonant optical nonlinearities in antimonide-based quantum-well systems in a wide range of carrier populations from nondegenerate to highly degenerate. The future development of the proposed devices will include fabrication of widely tunable terahertz emitters as well as integration with silicon photonics. Transfer of the technology to the arsenide or silicon platform will enable epi-side down mounting of large area arrays of the terahertz emitters to scale up the output terahertz power to tens of milliwatt level and perform terahertz beam shaping.