SBIR Phase I: Tunable Terahertz Quantum Cascade Lasers for Spectroscopy

这项小企业创新研究（SBIR）第一阶段项目将重点演示频率可调量子级联激光器（QCL），该激光器工作在太赫兹频率（1-10太赫兹），用于光谱学和非破坏性成像等应用。这种新型光源是基于外部微定位驱动器来驱动调谐机构来操纵QCL的光波导尺寸。这种操作有效地改变了波导的光学折射率和QCL的发射频率。频率调整将由电子驱动，导致300 GHz频率范围内的快速扫描（100 Hz）。可调谐的QCL将被安置在一个小尺寸的冷却器中，输出功率将大于100 μ W，比目前的商用系统提高了3个数量级。第二阶段的改进将导致在1.5到5太赫兹的中心频率范围内更大的可调谐范围。这个项目的更广泛的影响/商业潜力将是在光谱或光谱成像中检测和表征狭窄的气体线（MHz）或固体吸收特征（GHz），可用于学术、工业和政府研究。MEMS可调谐源的电气操作和低温系统的交钥匙特性将允许非专业研究人员访问太赫兹光谱区域。未来的应用包括纳入扫描源光学相干层析成像系统，用于无损评估（NDE）。太赫兹频率辐射在无损检测中特别有意义，因为它们能够穿透在红外和可见光波段不透明的材料，如结构泡沫、聚合物和油漆。潜在的应用包括航空航天工业中使用的泡沫结构完整性的验证；持续监控汽车行业的油漆工艺；以及用于控释制剂的药物片剂包衣的验证。

This Small Business Innovation Research (SBIR) Phase I project will focus on the demonstration of a frequency tunable quantum cascade laser (QCL) operating at terahertz frequencies (1-10 THz) for applications including spectroscopy and non-destructive imaging. This novel source is based on external micropositioning driver for actuated the tuning mechanism that manipulates the QCL's optical waveguide dimensions. This manipulation effectively changes the optical index of the waveguide and the emission frequency of the QCL. The frequency tuning will be actuated electronically, resulting in fast sweeps (100 Hz) over frequency ranges of 300 GHz. The tunable QCL will be housed in a small footprint cry cooler, and will have output powers greater than 100 µW - an improvement of 3 orders of magnitude over current commercial systems. Phase II improvements will result in larger tunable ranges at center frequencies ranging from 1.5 to 5 THz. The broader impact/commercial potential of this project will be in detection and characterization of narrow gas lines (MHz) or solid absorption features (GHz) in spectroscopy or spectroscopic imaging, useable for academic, industrial and governmental research. The electrical operation of the MEMS tunable source and the turnkey nature of the cryogenic system will allow non-expert researcher access to the terahertz spectral region. Future uses include incorporation into a swept-source optical coherence tomography system for non-destructive evaluation (NDE). Terahertz frequency radiation is of particular interest for use in NDE because they are able to penetrate materials that are opaque at infrared and visible wavelengths such as structural foams, polymers and paints. Potential applications include the validation of the structural integrity of foams used in the aerospace industry; continuous monitoring of paint processes in the automotive industry; and the validation of pharmaceuticals tablet coatings used in controlled release formulations.