Development of laser humidity sensor based on tunable diode laser absorption spectroscopy

Abstract

The sinusoidal root mean square (RMS) normalization method is proposed to measure humidity, and the ratio of the second harmonic peak-peak value and the sinusoidal RMS value is used as the system output, which can effectively eliminate the influence such as windows pollution and optical intensity fluctuation. The laser humidity sensor is developed, and reflective open gas cell is used. The structure of the optical system is simple, which is easy to be adjusted. Humidity calibration tests are carried out in the north china sea standard and metrology center of state oceanic administration, and the humidity measurement deviation is less than ±0.6% in the range of 30%RH ~ 80%RH. The comparison experiment was completed between the laser humidity sensor and the traditional humidity sensor in the national meteorological basic station. Experimental results show that the consistency of the humidity data is good, which proves the validity of sinusoidal RMS normalization method for measuring environmental humidity.