A broadband cavity ring-down spectrometer based on an incoherent near infrared light source

We report on the development of a cavity ring-down (CRD) spectrometer based on an incoherent broadband light source centered at 1,545 nm. One measurement spans over 46 nm. Due to the challenge of broadband CRD spectroscopy in the addressed spectral range, an extended measurement principle is developed. First successful measurements in the spectral range between 1,547 and 1,593 nm of a cavity filled with CO₂ are shown. In order to compare the experimentally determined data to values of the HITRAN database, the calculation of the expected values is discussed under consideration of the spectrometer’s spectral resolution. Comparison with the data based on the HITRAN database shows good agreement.