Tunable IR Lasers for Gas-Phase Sensing

高光谱质量，紧凑，坚固，基于半导体的可调谐激光源横跨中红外，3- 12 Pm，将极大地增强有源和远程传感器的能力。半导体材料和激光器的最新进展为覆盖整个红外分子指纹区域（包括关键的3-5 Pm和8-12 Pm大气窗口）的连续可调谐，高光谱纯度，高功率源提供了机会。光泵浦的高功率半导体激光源最近在整个红外领域得到了发展。这些应用通常需要高光束质量，“功率在一个桶”的性能，只有粗略的波长控制。相比之下，光谱应用更注重频谱质量和灵活性，而对宽带功率的重视程度较低。该计划的主要目标是开发集成光谱控制技术，以实现这些源的鲁棒性和敏捷性光谱使用，并证明它们对传感器的实用性。在新墨西哥大学和美国空军研究实验室（AFRL）的合作中，初步的工作已经证明，通过使用分布式反馈（DFB）光栅结构，激光器的线宽可以大大减少。在本研究中，该结构的设计和参数的变化将被研究，重点是窄线宽，高功率工作，以及在大波长范围内的连续单频调谐。对于光泵浦器件，额外的自由度是可用的，因为增益条纹是由光学配置定义的，并且是完全灵活的。横向啁啾光栅可用于提供连续调谐。这是半导体激光器调谐的一个全新的概念，并构成了计划研究的基础。基于该激光系统的增益带宽，预计连续调谐范围为数百cm -1，远远超过任何其他技术。本项目资助学生1名，博士后1名。新墨西哥大学是一所西班牙裔服务机构，拥有大量西班牙裔和美洲原住民学生。PI已经与印第安人社区的招募工作进行了强有力的互动。

ABSTRACTNSF- 0515547Brueck, StevenHigh spectroscopic quality, compact, robust, semiconductor-based tunable laser sources across the mid-IR, 3 - 12 Pm, would dramatically enhance the capabilities of active point and remote sensors Recent progress in semiconductor materials and lasers offers opportunities for continuously tunable, high spectral purity, high-power sources covering the entire IR molecular fingerprint region including the critical 3-5 Pm and 8-12 Pm atmospheric windows. Optically pumped, high-power semiconductor laser sources, have recently been developed across the IR. These applications typically demand high beam quality, "power-in-a-bucket" performance with only coarse wavelength control. In contrast, spectroscopic applications put a premium on spectral quality and agility with less emphasis on broadband power. The primary objectives of this program are to develop the integrated spectral control technologies necessary for robust and agile spectroscopic use of these sources and to demonstrate their utility for sensors.In a collaboration between UNM and AFRL, the Air Force Research Laboratory, preliminary work has demonstrated that the linewidth of lasers can be dramatically reduced by the use of a distributed feedback (DFB) grating structure. In this research, variations in the design and in the parameters of this structure will be investigated with emphases on narrow linewidth, high-power operation, and continuous, single-frequency tuning over a large wavelength range. For optically pumped devices, additional degrees of freedom are available since the gain stripe is defined by the optical configuration and is totally flexible. A transversely chirped grating can be used to provide for continuous tuning. This is a totally new concept for the tuning of semiconductor lasers and forms the basis of the planned investigation. Based on the demonstrated gain-bandwidth of this laser system, continuous tuning ranges of several hundreds of cm -1 are anticipated - far in excess of that available by any other technique.This program will support one student and one postdoctoral researcher. UNM is a Hispanic ServingInstitution with large populations of Hispanic and Native American students. The PI already has strong interactions with recruiting efforts in the Native American community.