Optical path length and absorption cross section optimization for high sensitivity ozone concentration measurement

Abstract

Long optical path length and strong ozone absorption wavelength are generally applied for high sensitivity ozone concentration measurement in ultraviolet absorption spectroscopy. However, high sensitivity of measurement cannot be achieved when the sensor approaches saturation. Here, we derive two equations based on Beer-Lambert law to optimize the sensitivity of measurement. Firstly, we optimize the optical path length for high sensitivity measurement of specific range of ozone concentration. Secondly, we optimize the absorption cross section for proper selection of ozone sampling wavelength to prevent sensor saturation. Simulation and experimental results show high sensor sensitivity for a gas cell of optimized optical path length. High sensitivity of measurement is achieved when the sensor is not saturated. We have validated the requirements for high sensitivity ozone concentration measurement through theoretical calculation, spectralcalc.com simulation and experiment.