Population inversion in fluorescing fragments of super-excited molecules inside an air filament
Population inversion in fluorescing fragments of super-excited molecules inside an air filament |
| Fig. 1. Experimental setup for measuring backscattered fluorescence gain in three mixture gases: 2% CH 4 , 2% C 2 H 2 , or 2% C 2 H 4 in air at 1#cod#x0A0;atm. We detected the CH signal at around 430#cod#x0A0;nm. The CPA was a Ti-sapphire laser which delivered 800#cod#x0A0;nm50 fs pulses and generated filaments at the center of the gas cell. The backward pointing arrows indicate the backscattered fluorescence light that was collected by a fused silica lens affixed to the fiber head coupled to the spectrometer. [ 7 ] |
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