Sensitive absorption measurements of hydrogen sulfide at 1.578 μm using wavelength modulation spectroscopy*
Xia Hua, Dong Feng-Zhong†, Wu Bian, Zhang Zhi-Rong, Pang Tao, Sun Peng-Shuai, Cui Xiao-Juan, Han Luo, Wang Yu
       
The Allan variance for 5 ppmv H2S.