Interference spectroscopy with advanced comb sources

光学频率梳是一种能产生非常短且稳定的光脉冲的激光器。通过在光学和电可测量频率之间提供精确而简单的联系，它们在2000年点燃了频率计量学的一场革命，这是一门测量振荡和时间的科学。守时很重要，因为大多数测量单位都与时间直接相关，因为这是我们人类可以最精确地测量的物理量。因此，当你为你的汽车购买一定数量的汽油或支付水电费时，你就依赖于国家实验室维持的国际时间标准。精确时间标准的更直接应用包括使用类似GPS的系统进行地理定位，以及在全球范围内同步所有金融交易。 频率梳无疑是有史以来生产的最精确的光源，因此它们有望在其他几个领域带来革命。首先也是最重要的可能是光学光谱学，这是一门通过测量不同波长(不同“颜色”)的光与物质的相互作用来确定气体、液体和固体的化学成分的科学。当你喝牛奶时，它的纯度已经用光谱仪进行了评估，当你查看天气预报来计划一个长周末时，你实际上是在利用卫星上的几个光谱仪来仔细观察大气。 梳子在显着改进光谱方面有很大潜力，但目前有几个缺陷阻碍了这一新工具的大规模采用。第一个因素是，它们是复杂而微妙的来源，需要高素质的研究人员来维护和操作。其次，它们本身并不能产生正确的“颜色”来审问物质。它们目前处于近红外(波长在1到3微米之间)，而光谱探测在中红外和远红外(从3到5微米和8到12微米)中工作得更好。 本申请中提出的研究计划将解决这些问题，并有助于使紧凑和坚固的中红外梳状光谱仪成为现实。将使用创新的芯片激光平台。这一平台将允许在一块芯片上放置几个激光，这样光谱仪就会变得很小，而且固有的坚固耐用，因为所有需要的光学功能最终都将放在一块玻璃中。 加拿大在光学光谱学方面拥有雄厚的工业基础，几个省份的公司向不同的细分市场销售仪器：从食品和药品生产线的质量控制的过程自动化，到安全、气象和环境监测的遥感。因此，更快、更灵敏的光谱仪不仅有助于生产更好、更安全的产品，改善天气预报或空气质量测量，而且还将直接支持加拿大高科技经济的传统优势。

Optical frequency combs are lasers that produce very short and stable light pulses. By providing a precise and simple link between optical and electrically measurable frequencies they ignited in 2000 a revolution in frequency metrology, the science of measuring oscillations and time. Time keeping is important because most measurement units are directly linked to time, as this is the physical quantity that we humans can measure most precisely. Hence, when you buy a volume of gas for your car or when you pay your utility bill, you rely on the international time standard maintained by national laboratories. More direct applications of a precise time standard include geo-localization using GPS-like systems and synchronizing all financial transactions on a global scale. Frequency combs are without a doubt the most precise optical sources ever produced and they accordingly promise revolutions in several other domains. The first and foremost is probably in optical spectroscopy, the science of determining the chemical composition of gasses, liquids and solids by measuring the interaction of light at different wavelengths (different “colors”) with matter. When you drink milk, its purity has been assessed using a spectrometer and when you check the weather forecasts to plan a long weekend, you are effectively making use of several spectrometers on satellites scrutinizing the atmosphere. Combs have a lot of potential to improve spectroscopy significantly but several shortcomings currently prevent a large-scale adoption of this new tool. The first factor is that they are complex and delicate sources requiring highly qualified researchers to maintain and operate. Second, they do not natively produce the right “color” to interrogate matter. They are currently in the near-infrared (wavelengths between 1 and 3µm) while spectroscopic sounding works better in the mid- and far-infrared (from 3 to 5µm and from 8 to 12µm). The research program proposed in this application will address these issues and contribute making compact and robust comb spectrometers in the mid-infrared a reality. An innovative chip laser platform will be used. This platform will allow putting several lasers on a single chip, such that the spectrometer will be small and inherently rugged because all needed optical functions will ultimately be put in a single piece of glass. Canada has a strong industrial base in optical spectroscopy, with companies in several provinces selling instruments worldwide to different market segments: from process automation for quality control in food and pharmaceutical production lines to remote sensing for security, meteorological and environmental monitoring. Faster and more sensitive spectrometers will thus not only contribute to better and safer products and to improved weather predictions or air quality measurements, but will also directly support a traditional strength of Canada's high-tech economy.