Fig. 1. Schematic of energy levels of three-level laser system for metastable Kr

Fig. 2. Schematic of the experimental setup for absorption experiment

Fig. 3. Residual probe light intensity with different wavelengths varying with time

Fig. 4. Measured data of absorption spectrum line and fitting profile(solidline) by traditional fitting method

Fig. 5. Measured data and fitting profile of absorption spectrum line at different time. (a) 23.8 μs; (b) 15.8 μs

Fig. 6. Variation of particle number concentration with time