High power quantum cascade lasers for terahertz applications

该计划的目标是开发单模太赫兹半导体激光器，在液氮温度下连续工作时发射超过100毫瓦的光功率，这比以前证明的高出两个数量级。增益介质将由GaAs/AlGaAs量子级联异质结构组成。这种窄带太赫兹源在诸如射电天文学、化学和生物传感以及用于识别隐藏武器、毒品和爆炸物的成像和光谱学等不同领域都有应用。其智力上的优点在于使用了新颖的波导结构，这种结构将微波工程的联合收割机技术与红外分布反馈激光器的技术相结合。由于太赫兹辐射的独特性质，相控阵天线结构将被纳入具有嵌入式量子级联增益介质的半导体微腔中。通过将太赫兹量子级联激光器带出研究实验室的模具，设想对太赫兹科学和技术领域的潜在变革性影响，到可以为重要应用建造实用仪器的情况。更广泛的影响是在纳米光子学，量子电子学，微细加工，和太赫兹技术的研究生和本科生的研究环境。研究内容将被纳入关于纳米光子学的新课程，并将通过参与外联活动展示，以培养高中学生的科学兴趣。一个计划是积极参与本科生在实验室的太赫兹研究活动。在太赫兹应用领域的新的研究合作将在不同的机构进行。

The objective of this program is to develop single-mode terahertz semiconductor lasers emitting more than hundred milliwatts of optical power in continuous-wave operation at liquid-nitrogen temperature, which is two orders of magnitude higher than that demonstrated previously. The gain medium will be comprised of GaAs/AlGaAs quantum-cascade heterostructures. Such narrow-band terahertz sources have applications in areas as diverse as radio-astronomy, chemical and biological sensing, and imaging and spectroscopy for identification of concealed weapons, drugs, and explosives. The intellectual merit is in the use of novel waveguide architectures that combine techniques from microwave engineering with those of infrared distributed-feedback lasers. Phased-array antenna structures will be incorporated into semiconductor microcavities with the embedded quantum-cascade gain medium, made possible owing to the unique properties of terahertz radiation. A potentially transformative impact on the field of terahertz science and technology is envisioned by bringing terahertz quantum-cascade lasers out of the mold of research laboratories, to a situation where practical instruments could be built for important applications.The broader impacts are in providing education in the areas of nanophotonics, quantum-electronics, microfabrication, and terahertz technology to graduate and undergraduate students within a research environment. Elements of research will be incorporated into a new course on nanophotonics, and will also be showcased to create scientific interest among high-school students through participation in outreach activities. A program is in place to actively involve undergraduate students in the terahertz research activities in the laboratory. New research collaborations in the area of terahertz applications will be pursued across different institutions.