Extending Remote Gas Sensing Range

Remote sensing technologies are necessary in order to increase the safety of emergency responders and give early warnings of chemical weapons attacks. The technology needs to be able to accurately identify multiple chemical species over extended ranges, even when signals are short-lived or in constant-flux. We propose to address this problem with the development of a dual-frequency comb spectroscopy based remote detection system. These systems provide a large spectral range and high resolution, allowing them to accurately identify multiple chemical species. In addition, spectral information is collected with high bandwidth, allowing for identification of chemicals within milliseconds. Our system will be enhanced with an adaptive optics module to compensate for the effects of air turbulence and allow for detection ranges much longer than one kilometer. During Phase I, we will upgrade our existing dual-frequency comb in order to allow for both combs to be phase-locked. This will increase the resolving power of the setup. Once upgraded, we will demonstrate our ability to identify multiple chemical species with high accuracy and at high bandwidth. In addition, we will demonstrate phase control of laser beams by converting a Gaussian beam into a Bessel beam with an adaptive optics module. Finally, we will determine the necessary beam control bandwidth in order to propagate the frequency comb beams as far as possible while still being able to correct for the effects of air turbulence. Our technology will have applications in detection of hazardous materials, environmental monitoring, and climate change studies, as well as applications in enforcement of international treaties pertaining to weapons of mass destruction.