CAREER: Continuous-wave Terahertz laser employing HTS Josephson junctions

建议编号：2045957首席研究员：Timothy M Bensman标题：Career：使用HTS Josephson结的连续波太赫兹激光器机构：纽约大学皇后学院非技术摘要在0.3万亿赫兹到1.5万亿赫兹之间工作的强大而轻巧的激光器将为许多应用提供飞跃，例如安全和超高速的无线数据网络，检测隐藏的药物和爆炸物，以及早期识别龋齿和皮肤癌。它们将远远超过目前在此频率范围内可用的激光和类似激光的电磁辐射源的能力，后者要么功率输出较低，要么太大、太重和太耗电，无法用于野外便携式应用。该项目建立了一种独特的基于高温超导体的新型激光技术，该技术将非常适合上述应用在此太赫兹频率范围内。到目前为止，这种类型的激光器产生的毫瓦级功率只在基本物理水平上进行了理论预测。该项目对这些想法进行了经验测试，并对技术进行了工程设计，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相机和夜视镜的微型制冷器。为补充超导研究项目，开展了一项科学推广活动方案。这些是基于超导悬浮实验，以激励高中生和社区大学生，特别是来自人口统计数据不足的人，进入STEM领域。一个研究生级别的课程模块专注于微电子的光刻制造技术，为学生在器件微制造研究中的职业生涯做好准备。技术摘要目前，大约0.3万亿赫兹到1.5万亿赫兹之间的相干辐射源都存在严重的工程缺陷，限制了它们的用途。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，要么非常笨重、笨重和耗电。在这种太赫兹范围内运行的用户友好型激光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防御技术。各向异性高温超导化合物Bi2Sr2CaCu2O8中的本征超导体-绝缘体-超导体(Josephson)结是最有希望填补太赫兹禁带的候选材料之一。这些本征约瑟夫森结可用于制造目前唯一提供可调谐、高功率和连续工作的紧凑型太赫兹激光光源。该项目设计了基于Bi2Sr2CaCu2O8约瑟夫森结的太赫兹激光光源，使这些器件的太赫兹功率输出至少提高数量级至1毫瓦或更高，同时将其工作频率范围至少增加一倍，达到至少1.0太赫兹。这些在太赫兹功率和发射频率方面的改进旨在即使在77开尔文或更高的工作温度下也是如此，以便最大限度地减少低温冷却要求。太赫兹源是通过在Bi2Sr2CaCu2O8晶体上进行图案化堆叠，使用光学光刻和Ar-离子研磨来微制造的。批量生产用于商业规模太赫兹激光应用的可行性将得到测试。最后，本项目的进一步研究目标是测量一种新型约瑟夫森等离子体在Bi2Sr2CaCu2O8中的行为。从实验上理解这种等离子体激元将有可能为太赫兹信号检测和混频设计一种全新的高效电子设备。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.