Interband cascade vertical surface emitting lasers for optofluidic biochemical sensors

该研究计划的目标是设计和演示用于中红外到远红外(IR)范围(2-50微米)的单波长和可调谐垂直腔面发射半导体激光器(VCSEL)二极管，并演示使用这些新光源进行痕量气体分析和单分子检测的中试光子传感系统。电泵浦低成本垂直腔面发射激光器在中红外波段的应用可能是基于激光传感应用的重大突破。实时痕量气体检测是一个快速增长的领域，应用于医疗诊断、过程控制、国家安全和环境空气质量监测等多个领域。例如，为了有效地监测温室气体以控制全球变暖，迫切需要一种传感器系统来检测和测量大气中的痕量气体，特别是钢铁加工、半导体铸造厂、汽车排放和农田牲畜排放的微量气体。同样，对于医疗领域，对呼气气体的敏感检测有可能成为对具有特定人类疾病或重要人体器官功能障碍特征的血液成分的非侵入性诊断测试。中红外(MIR)激光光谱是探测各种分子痕量气体的一种非常有效的工具，这些气体的基本振动吸收带从3微米到10微米。与化学探测器相比，基于激光的传感器系统也具有固有的优势，如快速数据收集和分析，以及在危险环境中进行非接触测量。新型低成本VCSEL光源的展示将有助于彻底改变这一市场，并使便携式传感器系统成为可能。

The objectives of this research program is to design and demonstrate single wavelength and tunable vertical cavity surface emitting semiconductor laser (VCSEL) diodes for the mid to far infrared wavelength (IR) range (2-50 microns) and to demonstrate a pilot photonic sensing system for trace gas analysis and single molecule detection using these new sources. The availability of electrically pumped low-cost VCSELs in the mid-IR wavelength region could be a major breakthrough for laser based sensing applications. Real-time trace-level gas detection is an area of fast growth with applications in such diverse fields as medical diagnostics, process control, national security, and environmental air quality monitoring. For example in order to effectively monitor the green-house gases to control global warming, there is a strong need for a sensor system for detecting and measuring trace gases in the atmosphere, especially those released by iron and steel processes, semiconductor foundries, auto emissions and livestock in farmlands. Similarly for the medical field, sensitive detection of the breath gases has the potential of becoming a non-invasive diagnostic test of components of blood that have characteristics of specific human diseases or dysfunctions of important human organs. Mid-Infrared (MIR) laser spectroscopy is an extremely effective tool for detection of various molecular trace gases which have fundamental vibrational absorption bands from 3 microns to 10 microns. Laser based sensor systems also have inherent advantages compared to chemical detectors such as rapid data collection and analysis and non-contact approach for measurements in hazardous environments. Demonstration of the new low cost VCSEL sources which can be arranged in two dimensional arrays will help to revolutionize this market and allow for portable sensor systems.