Absolute calibration of laser-induced fluorescence experiments by optical depth correction

Laser-induced fluorescence measurements are absolutely calibrated by correction of relative spatial fluorescence profiles for optical depth. The method is applicable if optical depths of fluorescence transitions are sufficiently high (mean optical depth τ̄≳0.3). For calibration two relative spatial density profiles are required. Measurements of absolute particle densities in a dc glow discharge are performed and compared to results of laser absorption spectroscopy. Absolute errors are found to be less than 20%. The calibration method is expected to be useful in experimental environments that are not accessible for other calibration methods, e.g., due to high optical depth.