SBIR Phase I: A diode laser system for high-resolution terahertz spectroscopy

这个小企业创新研究第一阶段项目将开发一种交钥匙激光系统，通过在固态光电混合器上对两个激光频率进行光外差混合，产生太赫兹辐射。在第一阶段，激光器将在0到1太赫兹的范围内相对调谐，绝对精度为2mhz，相对线宽为2mhz。为了实现这种性能，将使用新颖的频率偏移锁定技术来保持激光锁定在整个调谐范围内100%占空比到绝对频率参考。该激光系统将是全固态的，坚固耐用且易于使用，使其成为高分辨率连续波太赫兹光谱仪商业化的关键使能技术。高分辨率太赫兹光谱仪将为低能光/物质相互作用提供一个新的窗口，可以直接探测分子、DNA、生物分子和蛋白质的大振幅振动运动。高分辨率太赫兹光谱仪将在生物分子研究、药物开发和国土安全方面具有重要应用。蛋白质、DNA，甚至细菌和病毒等大分子都可以在太赫兹范围内具有光谱特征，这在生物威胁检测和研究与开发中具有明确的应用。研究表明，不同晶体形式的大分子在太赫兹状态下具有特征，这对药物摄取和药物过程控制具有重要影响。太赫兹光谱仪还可以帮助研发抗体/抗原受体，这对药物研究和生物分子研究很重要。最后，大分子的光谱特征可以对地雷修复工作以及运输和建筑安全的爆炸物检测产生重大影响。

This Small Business Innovation Research Phase I project will develop a turnkey laser system for creating terahertz radiation by optical heterodyne mixing of two laser frequencies on a solid-state photomixer. In Phase I the lasers will tune relative to each other over a range of 0 to 1 THz with 2 MHz absolute accuracy and 2 MHz relative linewidth. To achieve this performance, novel frequency-offset locking techniques will be used to maintain laser locking with 100% duty cycle to absolute frequency references during the entire tuning range. The laser system will be all solid state, robust, and easy to use, making it a key enabling technology, along with commercially available photomixers, for the commercialization of high-resolution cw terahertz spectrometers. High-resolution terahertz spectrometers will provide a new window into low-energy light/matter interactions and can directly probe large amplitude vibration motions of molecules, DNA, biomolecules, and proteins. A high-resolution terahertz spectrometer will have important applications to biomolecular research, pharmaceutical development, and homeland security. Large molecules such as proteins, DNA, and even bacteria and viruses can have spectroscopic signatures in the terahertz regime with clear applications to bio-threat detection and research and development. Research is showing that different crystalline forms of large molecules have signatures in terahertz regime with important consequences for drug uptake and process control of pharmaceuticals. Terahertz spectrometers could also aid in the R&D of antibody/antigen receptors important to drug research and biomolecular research. Finally, spectroscopic signatures of large molecules could have a large impact on explosives detection for landmine remediation efforts and transportation and building security.