Fig. 1. Schematic of experimental setup for nanosecond laser-induced PMMA plasma spectroscopy

Fig. 2. Time-resolved spectra of CN molecule (Δν=0). (a) Without spatial confinement cavity; (b) with spatial confinement cavity

Fig. 3. Evolution of CN (0-0) spectral peak intensity with delay time and wavelength. (a) Delay time; (b) wavelength

Fig. 4. Evolution of CN(0-0) spectral peak intensity with delay time. (a) Without spatial confinement cavity; (b) with spatial confinement cavity

Fig. 5. Evolution of CN(0-0) spectral peak intensity with laser energy at delay time of 5 μs

Fig. 6. Comparison of CN(Δν=0) spectra. (a) Without spatial confinement cavity; (b) with spatial confinement cavity

Fig. 7. Evolution of vibration temperatureof CN molecule with delay time under different laser energies. (a) 70 mJ; (b) 80 mJ