Optical sensors for air quality monitoring (gaz NO2, O3) – CAPTAIN

n this project an optical signal transfer based on plasmon excitation (SPR-Surface Plasmon Resonance) is going to be used. Several devices based on plasmon excitation have already shown their applicability for the detection of gaseous pollutants or chemical contaminants with high sensitivity and partial selectivity. However, their size, complexity and cost limit their use on a large scale. The innovative approach protected by a patent and proposed in the CAPTAIN project is also based on the excitation of plasmon modes but exploits a new effect of energy switching or the commutation of energy between propagated reflected orders. This tremendous effect allows to better exploit the plasmon modes (SPR) detection compared to existing sensors since it allows i) to increase the sensitivity by a factor of at least 2, ii) to simplify considerably the implementation of the sensor and iii) to overcome the problems of common mode variations.

First proof of concept (2021) with limit of detection below 10-6 RUI

This project has a direct impact on the environment and health, but also on the industry (automotive, process engineering, Smart City development, innovative industrial sensor networks and building automation ...). It focuses on the design of a new generation of potentially low-cost micro-sensors allowing their large-scale deployment thanks to their miniaturization and integration capability (on a miniature hybrid platform) with multi-gas detection potential (or a cocktail of pollutants).

Effect of roughness on surface plasmons propagation along deep and shallow metallic diffraction gratings
Hugo Bruhier, Isabelle Verrier, Thiaka Gueye, Christelle Varenne, Amadou Ndiaye, Olivier Parriaux, Colette Veillas, Stéphanie Reynaud, Jérôme Brunet, and Yves Jourlin.
Optics Letters - Vol. 47, Issue 2, pp. 349-352 - 2022 - doi.org/10.1364/OL.443659

Air pollution is the leading environmental cause of mortality. This worrying situation is not improving at the moment, since the emission levels of the main pollutants (nitrogen oxides NOx, ozone O3, volatile organic compounds VOCs and small particles SP) remain stable in the majority of major European cities. Beyond the environmental consequences reducing and monitoring air pollution is a real public health issue. Considering this serious conclusion it appears imperative to ensure a continuous measurement of the presence of these pollutants in ambient air in order to be able to implement means of remediation and methods of treatment, destruction or trapping of the effluent gases.
The CAPTAIN project (Optical Sensors for Air Quality Monitoring with regard to NO2, O3, pollutants), aims to develop a new generation of highly sensitivity, highly selective, robust, miniature, low-cost and energy-efficient optical micro sensors, dedicated to the monitoring of gaseous pollutants for the control of indoor and / or outdoor air quality. The project partners aim at an experimental demonstration (TRL 4 or 5) of sensors with a performance (sensitivity, sub-ppb detection, high selectivity, robustness to noise ...) beyond the state of the art. The targeted pollutants are the NO2 and O3.
While targeting sub-ppb detection thresholds, the solutions proposed by the CAPTAIN project in terms of selectivity and time drift will challenge the main limitations of currently available technologies (electrochemical, optical, Mox ...). They will eventually lead to dedicated micro sensors for indicative measurement of air pollution, thus meeting the requirements of Directive 2008/50 EC of the European Parliament.
In this project an optical signal transfer based on plasmon excitation (SPR-Surface Plasmon Resonance) will be used, combined with functional layers which will interact with the pollutants. Several devices based on plasmon excitation have already shown their applicability for the detection of gaseous pollutants or chemical contaminants with high sensitivity and partial selectivity. However, their size, complexity and cost limit their use on a large scale. The innovative approach protected by a patent and proposed in the CAPTAIN project is also based on the excitation of plasmon modes but exploits a new effect of energy switching or the commutation of energy between propagated reflected orders. This effect allows to better exploit the plasmon modes (SPR) detection compared to existing sensors since it allows i) to increase the sensitivity by a factor of at least 2, ii) to simplify considerably the implementation of the sensor and iii) to overcome the problems of common mode variations.
The CAPTAIN project is very multidisciplinary since it requires skills in material chemistry, physico-chemical characterization, optical signal transfer, optical modeling, micro-structuring, thin films, environmental metrology and implicitly sensors. This is why it involves 4 partners: 2 academic partners (Hubert Curien Laboratory and Pascal Institute) and 2 industrial partners (SILSEF and Environnement SA).
This project has a direct impact on the environment and health, but also on the industry (automotive, process engineering, Smart City development, innovative industrial sensor networks and building automation ...). It focuses on the design of a new generation of potentially low-cost micro-sensors allowing their large-scale deployment thanks to their miniaturization and integration capability (on a miniature hybrid platform) with multi-gas detection potential (or a cocktail of pollutants).