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光源横跨中IR，下午3-12点，将极大地增强有源点和远程传感器的能力。半导体材料和激光器的最新进展为连续可调、高光谱纯度、高功率光源提供了机会，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。光泵浦、高功率半导体激光光源最近在红外领域得到了发展。这些应用通常需要较高的光束质量、仅具有粗波长控制的“桶中功率”性能。相比之下，光谱应用更注重光谱质量和灵活性，而对宽带功率的重视较少。该计划的主要目标是开发稳健和灵活地使用这些光源所需的集成光谱控制技术，并展示它们对传感器的效用。在UNM和AFRL(空军研究实验室)的合作下，初步工作表明，通过使用分布式反馈(DFB)光栅结构，可以显著减少激光的线宽。在这项研究中，将研究这种结构在设计和参数上的变化，重点是窄线宽、高功率工作以及在大波长范围内连续的单频调谐。对于光泵浦器件，由于增益条带由光学配置定义并且完全灵活，因此可以使用额外的自由度。可以使用横向啁啾光栅来提供连续调谐。这对于半导体激光器的调谐来说是一个全新的概念，并构成了计划中的研究的基础。基于该激光系统显示的增益带宽，连续调谐范围有望达到数百厘米-1--远远超过任何其他技术所能提供的范围。该计划将支持一名学生和一名博士后研究人员。北卡罗来纳大学是一所西班牙裔服务机构，有大量的西班牙裔和美洲原住民学生。PI已经与美洲原住民社区的招聘努力有了很强的互动。

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.