Mikro/nanomechanické senzory pro monitorování atmosférických škodlivin

Abstract

The subject of the dissertation is research into micromechanical elements as detection elements in sensor systems. The aim was to design innovative solutions for a hazardous gas analyser operating on the principle of laser-diode absorption spectroscopy in the near and mid infrared regions and experimental functional material testing in the development of advanced photoacoustic detection techniques. The research involved a number of experiments aimed at improving spectroscopic techniques and verifying their possibilities for specific applications. The modulated wavelength (2f-WMS) spectroscopy method has been improved in particular through the use of high-quality DFB semiconductor lasers so that it now allows the measurement of high-resolution absorption spectra of substances in a flame environment. In addition, the technique of cantilever-enhanced photoacoustic spectroscopy (CEPAS) was applied, in particular using quantum cascade lasers for sensitive detection of substances released when burning biomass. With the arrangement used, detection limits at trace concentration levels were reached for a number of these substances. For sensitive detection purposes, micromechanical elements of so-called functional materials (HOPG, mica) have been developed as key elements of detection systems, operating successfully on the principle of cantilever-enhanced photoacoustic spectroscopy. A series of quantitative measurements have successfully tested these elements for the sensitive detection of dangerous gases and vapours. A gas and vapour analyser solution was also proposed using the "Quartz enhanced fotoacoustic spectroscopy" method, the detection limits of which were verified on the basis of quantitative measurements of carbon monoxide.