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Updated: Jul 7, 2026

Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
Published on: March 22, 2019
[Difference-frequency generation in PPLN and water vapor detection in air]
Lun-Hua Deng1, Xiao-Ming Gao, Zhen-Song Cao
1Laboratory of Atmospheric Optics, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. lhdeng@aiofm.ac.cn
Abstract:
The continuously tunable laser source has been realized in a periodically poled LiNO3 crystal based on difference frequency generation and quasi-phase-matching technique. The pump laser is an 1 W tunable Ti: Sapphire laser with a tunable region from 770 to 870 nm. The signal laser is an 1 W diode-pumped monolithic Nd : YAG laser. When the grating period is 20 microm and the temperature is tuned between room temperature and 200 degrees C, the generated wavelength of idler laser is around 2. 8 microm with the general power of .1-2 microW. The direct absorption spectra of (001 <-- 000) band of water in laboratory air were measured based on the laser source. The concentration of water vapor in the laboratory air was estimated with an absorption optical path of 8. 5 cm in open air.
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