The start of the project was slowed down by difficulties in recruiting a suitably qualified postdoc. Ones this difficulty was resolved, a first, proof-of-principle FFP-based gas analyzer for CO2 could be realized quickly. It allowed us to validate the working principle of FFP-based trace gas analysis using cavity-enhanced absorption spectroscopy. Due to the unusual working regime of this miniaturized analyzer, no established signal extraction method was available when the project started. We have developed two different methods that are compatible with this working regime and have tested their performance, starting with the first proof-of-principle demonstration and then in increasingly more quantitative measurements. Based on the experience gained with this first prototype, minimum viable products (MVPs) containing all essential components in a single, portable housing have been realized for CO2 and for methane. The methane MVP has been taken to a laboratory of NaTran (formerly GRT Gaz, French natural gas transmission system operator), where measurements have been done at precisely calibrated concentrations, pressures and temperatures, allowing an initial evaluation of the key factors limiting the analyzer's sensitivity, dynamic range, and drift. One important experimental result was that no measurable saturation effects occur over a wide range of laser powers, even for powers beyond the intended working range of the analyzer. Based on these results, the method yielding more promising results was selected and its performance optimized in several iterations. This led to rapid improvements of the sensitivity which are still going on, but justify our expectations of competitive datasheet specifications with the next two months.
In parallel with this research and characterization work, the FFP cavity forming the core of the instrument was developed from a delicated laboratory instrument requiring weeks of assembly and adjustment by a PhD-level scientist, into a robust component with a industry-grade robustness and housing that can be assembled by a technician following a standardized procedure.
As a result of this work, the startup company Mirega.com which has been created during the project phase, has been able to introduce its first product, a tunable optical filter. First devices have been delivered to customers well before the end of the project. Most importantly, the miniature gas analyzer received remarkable attention by potential customers, and the PoC project results enabled Mirega to secure funding for the remaining steps of product development. Market introduction of the gas analyzer is planned for early 2027.
