Fig. 1. Schematic of XPNaL operation mechanism

Fig. 2. Schematic of experimental device for testing fluorescence lifetime

Fig. 3. Fluorescence spectrum of sodium-ethane excimer pairs sodium D1 and sodium D2 lines at 250 ℃

Fig. 4. Time-resolved fluorescence spectra of sodium-ethane excimer pairs sodium D2 line. (a) Fluorescence decay curve; (b) linear fitting curve

Fig. 5. Fluorescence lifetimes of sodium D1 line and sodium D2 line excited by laser with wavelength of 553 nm at different operation temperatures

Fig. 6. Fluorescence lifetimes of sodium D1 line and sodium D2 line excited by laser with different wavelengths at 250 ℃

Fig. 7. Measured ASE signals of sodium-ethane excimer pairs sodium D1 line and sodium D2 line at different temperatures. (a) 300 ℃; (b) 340 ℃