CAREER: Continuous-wave Terahertz laser employing HTS Josephson junctions

提案编号：2045957主要研究者：Timothy M Benseman职务：职业生涯：采用高温超导约瑟夫森结的连续波太赫兹激光器机构：CUNY Queens College非技术摘要工作频率在0.3万亿赫兹和1.5万亿赫兹之间的强大而轻便的激光器将为许多应用提供飞跃，例如安全和超快的无线数据网络，隐藏毒品和爆炸物的检测，以及蛀牙和皮肤癌的预警识别。它们将远远超过目前在该频率范围内可用的激光器和类似激光器的电磁辐射源的能力，这些电磁辐射源要么具有低功率输出，要么太大、太重且太耗电而不能用于现场便携式应用。该项目建立了一种基于高温超导体的新型激光技术，该技术将非常适用于该“太赫兹间隙”频率范围内的上述应用。到目前为止，这种激光器的毫瓦级功率仅在理论上预测，在基础物理学的水平。该项目以经验为基础测试这些想法，并设计技术以使其可用于部署。这项技术的低温冷却要求利用了已经用于红外摄像机和夜视镜的微型低温冷却器。为了补充超导研究项目，进行了科学推广活动计划。这些都是基于悬浮实验，以激励高中生和社区大学生，特别是来自代表性不足的人口，进入干领域。一个研究生水平的课程模块侧重于微电子学的光刻制造技术，并为学生在器件微细加工研究方面的职业生涯做好准备。技术摘要目前，在大约0.3万亿赫兹和1.5万亿赫兹之间可用的相干辐射源都有严重的工程缺陷，限制了它们的实用性。在这些频率下工作的现有技术要么产生非常低水平的输出功率，要么非常重、体积大且耗电。在这种“太赫兹间隙”范围内工作的用户友好型激光器将彻底改变许多领域，包括高带宽数据传输，科学和医学成像以及安全和国防技术。高温超导化合物Bi_2Sr_2CaCu_2O_8中的叠层“本征”超导体-绝缘体-超导体（Josephson）结是填补“太赫兹能隙”的最有希望的候选材料之一。这些本征约瑟夫森结可用于设计目前唯一提供可调谐性、高功率和连续波操作的紧凑型太赫兹激光源。该项目设计了基于Bi 2Sr 2CaCu 2 O 8约瑟夫森结的太赫兹激光源，以实现这些器件的太赫兹功率输出至少增加一个数量级，达到1毫瓦或更高，同时还将其工作频率范围至少增加一倍，达到至少1.0太赫兹。即使在77开尔文或更高的操作温度下，这些太赫兹功率和发射频率的增强也是有针对性的，以便最小化低温冷却要求。采用光刻和氩离子铣削技术在Bi 2Sr 2CaCu 2 O 8晶体上制作了太赫兹源。商业规模的太赫兹激光应用的可行性将进行测试。最后，本项目的进一步研究目标是测量Bi_2Sr_2CaCu_2O_8中一种新型约瑟夫森等离子体的行为。通过实验了解这种等离子体激元将使设计一种全新的高效电子设备用于太赫兹信号检测和混合成为可能。该奖项反映了NSF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。

Proposal Number: 2045957Principal Investigator: Timothy M BensemanTitle: CAREER: Continuous-wave Terahertz laser employing HTS Josephson junctionsInstitution: CUNY Queens CollegeNontechnical AbstractPowerful and lightweight lasers that operate at frequencies between 0.3 trillion Hertz and 1.5 trillion Hertz will offer a leap forward for numerous applications, such as secure and ultrafast wireless data networking, detection of concealed drugs and explosives, and early-warning identification of tooth decay and skin cancer. They will far surpass the capabilities of lasers and laser-like electromagnetic radiation sources currently available in this frequency range, which either have low power output, or are too large, heavy, and power-consuming to be used in field-portable applications. This project establishes a new type of laser technology uniquely based on high-temperature superconductors that will be ideal for the above applications in this ‘terahertz gap’ frequency range. To date, milliwatt-level power from this type of laser has only been theoretically predicted, at the level of fundamental physics. This project tests the ideas empirically and engineers the technology to make it available for deployment. The cryocooling requirements of this technology take advantage of micro-cryocoolers that are already used for infrared cameras and night vision goggles. To complement the superconductivity research project, a program of scientific outreach activities is performed. These are based on superconductive levitation experiments to inspire high schoolers and community college students, particularly from underrepresented demographics, into STEM fields. A graduate-level course module focuses on lithographic fabrication techniques for microelectronics and prepares students for careers in device microfabrication research.Technical AbstractAt present, the sources of coherent radiation available between approximately 0.3 trillion Hertz and 1.5 trillion Hertz all have serious engineering drawbacks that limit their usefulness. Existing technologies that work at these frequencies either generate very low levels of output power, or are very heavy, bulky, and power-consuming. User-friendly lasers operating in this ‘terahertz gap’ range would revolutionize a number of fields, including high-bandwidth data transmission, scientific and medical imaging, and security and defense technologies. Stacked ‘intrinsic’ superconductor-insulator-superconductor (Josephson) junctions in the extremely anisotropic high-temperature superconducting compound Bi2Sr2CaCu2O8 are one of the most promising candidates for filling the ‘terahertz gap’. These intrinsic Josephson junctions can be used to engineer the only compact terahertz laser source that currently offers tunability, high power, and continuous-wave operation. This project engineers terahertz laser sources based on Bi2Sr2CaCu2O8 Josephson junctions to achieve at least an order-of-magnitude enhancement in the terahertz power output of these devices to 1 milliwatt or more, while also at least doubling their operating frequency range to at least 1.0 terahertz. These enhancements in terahertz power and emission frequency are targeted even at operation temperatures of 77 Kelvin or more, in order to minimize cryocooling requirements. Terahertz sources are microfabricated by patterning stacks on Bi2Sr2CaCu2O8 crystals using optical lithography and argon-ion milling. The feasibility of doing this at volume for commercial-scale terahertz laser applications will be tested. Finally, a further research aim of this project is to measure the behavior of a novel type of Josephson plasmon in Bi2Sr2CaCu2O8. Experimentally understanding this plasmon would make it possible to engineer an entire new class of highly efficient electronic devices for terahertz signal detection and mixing.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.