Laser-based diagnostics are a powerful tool for identifying and quantifying chemical species in the atmosphere, with applications in weapons threat detection, industrial process verification and monitoring, and climate change mitigation. The recent creation of precise, broadband laser spectrometers, such as dual frequency comb spectrometers, has opened up new possibilities in these fields, driven by advanced capabilities such as speciation of complex large molecules, simultaneous quantification of multiple species, and isotopic detection. However, in order to realize these real-world benefits, it is necessary to develop optical transceivers able to transmit broadband laser signals over long atmospheric distances with high signal to noise ratio. For an optical transceiver to achieve this goal it must simultaneously achieve efficient signal detection, with precise pointing precision to hit distant targets, and stand up to harsh weather conditions. In Phase I, LongPathâs field-proven broadband transceiver design will be modified to improve the targeting precision of the transceiver by an order of magnitude. The transceiver will also implement a new signal receiving subsystem for a 3x improvement in efficiency while improving environmental robustness. These advancements will be demonstrated by using this prototype transceiver to perform sensitive, multi-species dual frequency comb detection of atmospheric trace gases over a 10 km atmospheric path, verifying the high signal to noise capabilities of the design over long distances. Expanding remote gas detection range will make this technology accessible to a number of beneficial applications. This includes the early detection and fast response to nuclear and chemical weapons manufacturing, and verification of compliance mechanisms. In the energy sector, increased-range capabilities for trace gas sensing enables cost-effective fugitive emissions detection and repair for the oil and gas industry
