Visser, BradleyRöhrbein, JannisSteigmeier, PeterDrinovec, LukaMočnik, GrišaWeingartner, Ernest2024-01-192024-01-1920201867-854810.5194/amt-13-7097-2020https://irf.fhnw.ch/handle/11654/43695https://doi.org/10.26041/fhnw-7636We have developed a novel single-beam photothermal interferometer and present here its application for the measurement of aerosol light absorption. The use of only a single laser beam allows for a compact optical set-up and significantly easier alignment compared to standard dual-beam photothermal interferometers, making it ideal for field measurements. Due to a unique configuration of the reference interferometer arm, light absorption by aerosols can be determined directly – even in the presence of light-absorbing gases. The instrument can be calibrated directly with light-absorbing gases, such as NO2, and can be used to calibrate other light absorption instruments. The detection limits (1σ) for absorption for 10 and 60 s averaging times were determined to be 14.6 and 7.4 Mm−1, respectively, which for a mass absorption cross section of 10 m2 g−1 leads to equivalent black carbon concentration detection limits of 1460 and 740 ng m−3, respectively. The detection limit could be reduced further by improvements to the isolation of the instrument and the signal detection and processing schemes employed.en620 - Ingenieurwissenschaften und Maschinenbau01A - Beitrag in wissenschaftlicher Zeitschrift7097-7111