Project Acronym: ATMO-SENSE
Full title: Novel portable, ultra-sensitive, fast and rugged trace gas sensor for atmospheric research based on photothermal interferometry
Project duration: 45 months
Coordinator: TU Wien – Institute of Solid State Electronics
Contact: Dr. Borislav Hinkov
Project website address:
https://fke.tuwien.ac.at/forschung/atmo_sense/project_overview/
Executive summary
The project ATMO-SENSE aims at taking the next steps towards the realization of a generic gas sensing platform characterized by high sensitivity, fast response time, rugged operation and low power consumption. The photonic sensing concept to be further developed and refined is based on the so called Interferometric Cavity-Assisted Photothermal Spectroscopy (ICAPS), which was recently developed and patented at TU Wien. In ICAPS, sensitivity and ruggedness strongly benefit from miniaturization. This is in strong contrast to classical absorption measurements, where an increase in sensitivity is typically achieved, by an increase in the optical path length.
Due to its unique characteristics ICAPS can be applied to a wide range of different gas sensing applications, like:
- Environmental trace gas monitoring (CO2, CH4, N2O …)
- Medical applications (e.g. exhaled breath gas analysis)
- Manufacturing / production (e.g. process monitoring and process control)
We have selected an application scenario in the area of Environmental Monitoring, where measurement speed, sensitivity, ruggedness and low power consumption are crucial. We plan to analyze fluxes of important trace gas molecules (N2O, CO2, O3) in the atmosphere and want to develop the photonic concept which allows performing such measurements in the future.
The ability to measure fluxes of trace chemical species in the atmosphere is of crucial importance in modern environmental research and reveals information on the mass transport of these chemical components. By analyzing these fluxes, insight in complex transport and exchange phenomena like e.g. geochemical compartments, atmospheric information and NxOy emission of different bacteria can be obtained.
Final project summary
The project ATMO-SENSE took the next step in the realization of a generic gas sensing platform. The sensor is based on mid-infrared photonic sensing, exploiting “interferometric cavity-assisted photothermal spectroscopy” (ICAPS), developed and patented at TU Wien.
In strong contrast to traditional absorption spectroscopy, where sensitivity scales with optical path length, sensitivity and ruggedness in ICAPS strongly benefit from miniaturization, enabling the use in gas sensing applications, such as: environmental trace gas monitoring, medical applications like exhaled breath gas analysis and manufacturing, e.g. in process control.
We addressed an application scenario in environmental trace gas monitoring, where sensitivity, measurement speed, ruggedness and low power consumption are crucial figures of merit. The goal was to measure atmospheric fluxes of important greenhouse trace gas molecules including CO2, N2O and CH4. Having access to time resolved concentrations of multiple chemical components up to sub- parts-per-billion (ppb) concentrations, reveals important information on mass transport of the chemical components. By detailed analysis of these fluxes, insight in complex transport and exchange phenomena including e.g. geochemical compartments, atmospheric information and NxOy emission of different bacteria can be obtained. The results of ATMO-SENSE demonstrate the suitability of ICAPS, to measure such fluxes.
Three major achievements were realized in the project. First of all, the mid-IR excitation laser used for tracegas probing was substituted with an interband cascade laser (ICL). ICLs are known for their very low thermal heat dissipation, supporting small and compact sensors. In collaboration between “nanoplus” and the “Optoelectronic Materials” group at TU Wien, newly developed ring-cavity ICLs were realized, with circular optical output beams and topside periodic grating for vertical light outcoupling. The ring-ICLs were implemented in the ICAPS sensor of the “process analytics” group (TU Wien), together with further improvements like e.g. improved low-noise detection techniques. The result is a field-deployable, batterydriven ICAPS prototype with the footprint of a shoebox, capable of measuring the isotope 12CO2 to a limit of detection of 240 ppb in ambient air.
