EAGER: Active Modelocking of Quantum Cascade Lasers

知识优势：目前还没有紧凑的短脉冲（10ps）中红外激光源。提出的研究将探讨抑制空间孔燃烧作为实现自启动、短脉冲量子级联激光器（QCL）源的一种手段。PI将根据概念增益结构分析可实现稳定运行的参数范围。这种模拟将使我们对这种工程结构中的相干物理有更深入的了解。该结构的初步概念来源于早期实现脉冲的概念，但不能自启动，最近由PI开发。该器件将基于交错增益和量子相干吸收周期的概念，可以在QCL激光器结构的受控生长过程中制造。这种交错应达到抑制有害的连续波和有利于稳定的脉冲操作。随着驱动参数的变化，量子相干吸收有望提供激光源的鲁棒锁模。更广泛的影响：这项探索性研究将为新型脉冲QCL结构的设计奠定基础，这是多种医疗和传感应用所需的工具。事实上，许多感兴趣的物种在中红外波段有很强的光谱特征。这一及时的研究也将为学生的培养提供一个很好的平台。此外，这项工作将利用以普林斯顿大学为中心的NSF MIRTHE中心，该中心开发qcl并探索其应用；MIRTHE中心有必要的设备来实验验证根据本提案获得的理论结果。

Intellectual Merit:There are currently no compact, short-pulse ( 10 ps) mid-IR laser sources. The proposed research will investigate the suppression of spatial hole burning as a means to achieve a self-starting, short-pulse quantum cascade laser (QCL) source. The PI will analyze the parameter range that would achieve stable operation, based on a conceptual gain structure. This simulation will yield a deeper understanding of the physics of coherence in such engineered structures. Preliminary concepts of the structure, derived from earlier concepts that achieved pulsing, but that could not self-start, were recently developed by the PI. The device would be based on the concept of interleaved gain and quantum coherent absorbing periods, which can be fabricated during controlled growth of the QCL laser structure. This interleaving should achieve suppression of deleterious continuous waves and favor stable pulsed operation. The quantum coherent absorption is expected to provide robust mode-locking of the laser source as drive parameters are varied.Broader Impact:This exploratory research will set the design space for a new pulsed QCL structure, which is a needed tool for multiple medical and sensing applications. Indeed many species of interest have strong spectral signatures in the mid infrared. This timely research will also be a good platform for student training. Additionally, this effort will leverage the NSF MIRTHE Center, centered in Princeton University, which develops QCLs and explores their applications; the MIRTHE center has the necessary equipment to experimentally verify the theoretical results obtained under this proposal.