Seminarium Optyczne

Optical detectors of formaldehyde and ethane (cancer biomarkers) in air exhaled from human lungs will bepresented. Application of the sensor is also possible for free atmosphere enabling continuous assessment ofair quality.Principle of the sensor operation is based on light absorption at wavelength tuned to spectral line(fingerprint) of the compound of interest. The measurement is performed in mid infrared range. In order toachieve the best immunity against typical interferents, which might occur at high concentration in humanbreath (water vapour -5%, carbon dioxide - 5%, methane -up to 10 ppm), the pressure reduction is applied.That leads to narrowing and separation of the absorption lines of various compounds due to limitation of thecollisional broadening.Multipass absorption spectroscopy is applied. Custom made multipass cells are used in the experimentalsystem. Original method of optical interferences quenching by wavelength modulation and signal averagingwill be presented. It provides opportunity to efficiently suppress undesired fringes occurring in multipass celland to increase the sensitivity of the spectroscopic system. The approach is reproducible, does not requireany mechanical and optical elements and can be adapted to various optical systems.Application of these approaches enables to achieve the detection limit of about several ppb for bothformaldehyde and ethane. Such sensitivity is better than the morbid level of the biomarkers.

Seminarium z użyciem połączenia internetowegohttps://zoom.us/j/97696726563(meeting ID: ID 97696726563, password: 314297)