Fig. 1. Absorption spectrum of water in the wavelength range of 1840−1900 nm水在1840−1900 nm波段的吸收谱线

Fig. 2. Influences of laser linewidth on the detected absorption lines around 1870 nm.不同激光线宽对1870 nm附近吸收谱线的影响

Fig. 3. Linewidth compression design of laser based on fiber saturable absorber (WDM, wavelength division multiplexer; OC, output coupler; ISO, isolator; FSA, fiber saturable absorber; FP filter, Fabry Perot filter).基于光纤可饱和吸收体的激光器线宽压缩光路设计(WDM, 反射式波分复用器; OC, 输出耦合器; ISO, 光纤隔离器; FSA, 光纤可饱和吸收体; FP filter, 法布里-珀罗滤波器)

Fig. 4. Output pulse train of laser at low pump power.低抽运功率下激光器脉冲输出序列

Fig. 5. Output pulses in a half scanning period at low pump power: (a) Pulse train; (b) a single pulse.低抽运功率下半个扫描周期内的输出脉冲　(a)脉冲序列; (b)单个脉冲

Fig. 6. Long-time output power record of laser at continuous wave operation.连续运转模式下激光器的长时间输出功率监测

Fig. 7. Instantaneous output power of laser at continuous wave operation连续运转模式下激光器的瞬时输出功率监测

Fig. 8. Typical output spectrum of laser with fiber saturable absorber.加入光纤可饱和吸收体后激光器典型输出光谱

Fig. 9. Laser linewidth measured with a scanning Fabry-Perot interferometer.法布里-珀罗干涉仪扫描得到的激光器线宽特性

Fig. 10. Oscillating laser modes measured with polarization control: (a) Dual modes; (b) single mode.偏振控制条件下激光器输出纵模特性　(a)双纵模; (b)单纵模

Fig. 11. Measured absorption signal: (a) HgCdTe detector; (b) InGaAs PDA detector.实验测得的吸收信号:　(a) HgCdTe探测器; (b) InGaAs PDA探测器

Fig. 12. Typical direct absorption spectrum in a single scanning period. The insert is the enlarged local absorption spectrum.典型的单个激光器扫描周期内测量的直接吸收光谱(内插图为局部的吸收光谱放大图)

Fig. 13. Absorption spectra of water from 1856 nm to 1886 nm1856—1886 nm范围内水的吸收光谱数据

Fig. 14. Absorption lines and corresponding residuals of water in 1870—1880 nm wavelength range: (a) Absorption lines; (b) residuals.1870—1880 nm范围内吸收谱线及残差　(a)吸收谱线; (b)残差