Tunable mid-infrared ultrafast fiber laser sources for remote sensing applications - I2I phase I

在3到5微米的波长范围内，与大多数碱性分子(如H2O、CH4和CO2)的振动模式相比，具有独特的特征。因此，该区域发射的宽带和相干光源是识别和监测特定体积或远程的分子物种的理想工具。虽然这些中红外激光器有望获得巨大的市场机会，但由于其有限的性能、较高的复杂性和固有的获取和维护成本，现有的光源一直在努力进入商业领域。在这个I~2I方案中，我们提出了一种基于氟化物玻璃纤维的简单而新颖的方法来产生高稳定的宽带光谱，该光谱可以在中红外光谱区连续调谐。该激光系统由一个产生2.8微米超短脉冲的光纤振荡器和一个用于放大和红移3微米以上脉冲的外部增益光纤组成。由NSERC I2I计划和University Laval资助的一项市场研究表明，这种基于超快光纤的激光器将是温室气体主动遥感的理想来源，更具体地说，是检测石油和天然气行业的甲烷泄漏。因此，这种源将被加固和优化，以便它可以在现场使用，并在3.4微米范围内有效地调谐，在那里，CH4键具有强烈的光谱特征。ABB和气体羽流成像等工业合作伙伴已经对这种来源的开发表现出了浓厚的兴趣。正如我们的合作伙伴DRDC Valcartier所展示的那样，由于这种中红外激光器具有独特的时间和光谱特性，它可以很容易地应用于其他几种潜在的应用，从中红外超连续谱到主动对抗。该光源的开发将触发我们集团一直在开创的氟化物光纤激光技术的转让，使我们实验室的一家加拿大初创公司以及我们的工业合作伙伴受益。

The wavelength region ranging between 3 to 5 microns possesses unique features in relation to the modes of vibration of most basic molecules such as H2O, CH4 and CO2. Broadband and coherent sources of light emitting in this region are therefore the ideal tools to identify and monitor molecular species in a given volume or remotely. Although huge market opportunities are expected for these mid-infrared lasers, existing sources have striven to enter the commercial realm due their limited performances, their high complexity and inherent cost of acquisition and maintenance. In this I2I proposal, we propose a simple and novel approach based on the use of fluoride glass fibers for the generation of a highly stable, broadband spectrum that can be continuously tuned in the mid-IR spectral region. This laser system consists of a fiber oscillator that generates ultrashort pulses at 2.8 microns and an external gain fiber for the amplification and redshifting of those pulses above 3 microns. A market study funded by the NSERC I2I program and Université Laval showed that such ultrafast fiber based lasers would be the ideal source for active remote sensing of greenhouse gas and more specifically for the detection of methane leaks in the oil and gas industry. This source will thus be ruggedized and optimized so that it can used on the field and be efficiently tuned over the 3.4 microns region, where CH4 bonds have a strong spectral signature. Industrial partners such as ABB and Gas Plume Imaging have already showed their keen interest for the development of such source. As this mid-IR laser possess unique temporal and spectral properties, it can be easily adapted for several other potential applications ranging from mid-IR supercontinuum generation to active countermeasures, as demonstrated by our partner DRDC Valcartier. The development of this source will trigger the transfer of the fluoride fiber laser technology that our group have been pioneering to the benefit of a Canadian startup arising from our laboratory as well as to our industrial partners.