Multi-wavelength tunable lasers for gas spectroscopy

在流程工业、环境和医疗应用中，同时快速测量多种气体的浓度以提供实时信息是非常重要的。例子包括：-测量燃烧原料和废气，这对减少碳排放很重要。-天然气工业和沼气生产工业中碳氢化合物和硫化氢的检测--工业中有毒物质的检测，如氨和氟化氢--呼吸气体诊断，以诊断和治疗哮喘、糖尿病、肾脏疾病、囊性纤维化等疾病。-测量短期气体种类，以改善城市空气质量并了解影响气候变化的重要大气过程。这些活动给工业用户带来了一个重大的测量问题。工业气体检测主要由复杂而昂贵的实验室设备进行采样，这些设备无法进行实时测量，甚至会通过样品管道中的冷凝和/或反应影响样品的组成。小型超低成本设备也是可用的，但这些设备不能提供工业应用所需的稳定性或气体种类专一性。许多感兴趣的气体在光谱的近红外区(1.3-2.5微米)吸收特定和特征波长的光。利用一种合适的激光光源，其发射波长已知且受控制，这一特性构成了一种强大的检测气体和测量其浓度的方法的基础。我们的新的光学气体检测方法，基于一种新型光源的开发，将使多种物种检测以及对不稳定物种的检测成为可能，这两种情况在现有技术下都是很难实现的。这些来源的演示最初将包括检测碳氢化合物、二氧化碳和一氧化碳，然后导致测量不稳定的物质，如硫化氢和氨。

In process industry, environmental and medical applications, it can be important to measure the concentration of many gas species simultaneously and rapidly, to give real-time information. Examples include; - Measurement of combustion feedstocks and effluent gases, important in the drive for reduced carbon emissions. - Detection of hydrocarbons and hydrogen sulfide in the natural gas industry and biogas generation industries - Detection of toxic species in industry, such as ammonia and hydrogen fluoride - Breath gas diagnostics, to diagnose and anage diseases such as asthma, diabetes, renal disease, cystic fibrosis and others. - Measuring short-lived gas species, to improve urban air quality and understand important atmospheric processes affecting climate change. These activities present a significant measurement problem to industrial users. Industrial gas detection is dominated by complex and expensive laboratory equipment with sampling that precludes real-time measurement and can even affect the composition of the sample through condensation and / or reaction in the sample pipework. Small ultra-low-cost devices are also available, however these do not offer the stability nor the gas species specificity needed for industrial applications. Many gases of interest absorb light at specific and characteristic wavelengths in the near infrared region of the spectrum (1.3 - 2.5 microns). Using a suitable laser source whose emission is at known and controlled wavelengths, this property forms the basis of a powerful method to detect gases and measure their concentrations.Our new approach to optical gas detection, based on development of a new class of optical sources, will enable both multi-species detection as well as detection of unstable species, both of which are difficult to impossible with existing technology. Demonstration of these sources will initially include detection of hydrocarbons, carbon dioxide and carbon monoxide, then lead on to measurement of unstable species such as hydrogen sulfide and ammonia..