Traditional humidity measurement methods include dry-wet ball method, condensation method, humidity-sensitive capacitance, and dew point method, but they are affected by factors such as wind speed, temperature, convenience of measurement, and measurement environment. The tunable semiconductor laser absorption spectroscopy (TDLAS) humidity sensor developed by the Institute of Semiconductors of the Chinese Academy of Sciences uses non-contact measurement. The source line width is narrow to effectively avoid cross-infection. The green laser pointer is suitable for humidity measurement under complex conditions.
The advantages of TDLAS technology in measuring humidity are:
First, high reliability and long life. The core device life of the host is more than five years. At the same time, the probe is passive and can be used for a long time, which greatly reduces the maintenance cost in the later period.
Second, no need to frequently calibrate. Due to the non-contact measurement, the core sensor is not disturbed by complicated working conditions and has high stability;
Third, high precision. The linearity of the wettability characteristic curve of TDLAS technology is good, and the linearity R2≥0.999, which is much higher than the accuracy requirement of the national HJ75-2017;
Fourth, full range measurement. TDLAS technology can truly achieve 0-100% RH full-scale measurement. In the case of low humidity, the lower limit of measurement can reach 1ppmv, and in high humidity conditions, it can be stably measured close to the condensation saturated 100% RH humidity.
The core technology of TDLAS has reached the international advanced level and is of great significance in the application of humidity. At present, TDLAS technology has been widely used in environmental protection, industry, meteorological industry, and military industry. TDLAS technology has been well received by users in high-altitude room temperature measurement of domestic drones, high-humidity environment monitoring in cultural relics, and humidity monitoring of data center IDC. The application of Chinese objects has filled the gaps in domestic and foreign markets.