Emission study of C₂and CN in laser-created carbon plasma under nitrogen environment

Abstract

Emission spectroscopy diagnostics of carbon plasma created by Nd–Yag laser ablation of a graphite target in nitrogen atmosphere is presented. The influence of the laser energy density in the range of 3–60 J cm−2 on the evolution of the maximum emission intensity and the time of flight of the temporal profile of C2 Swan band and CN violet system is studied at 3 mm from the target surface and at two nitrogen pressures 0.5 and 1 mbar. It has been observed that for fluences ⩽10 J cm−2, the C2 and CN evolutions have the same behaviour and for higher fluences, their evolutions are quite different. For this purpose, a study of the spatio-temporal evolution of the C2 and CN as well as neutral and ionic atomic species of carbon and nitrogen is performed for two values of laser fluences, 8 and 35 J cm−2. The different processes leading to CN formation are proposed and discussed.

Early stage expansion and time-resolved spectral emission of laser-induced plasma from polymer

“…The initial increase of emission intensity from CN molecules indicates the contribution from the recombination between atomic or molecular carbon in the plasma and nitrogen molecules in air. Such recombination has been observed in different circumstances [11,[15][16][17][18][19]. Recombination time constant of several hundreds of nanoseconds can be well fitted by considering involved chemical reactions C 2 + N 2 !…”

Emission features of femtosecond laser ablated carbon plasma in ambient helium

“…36 Thus, there must be mechanisms taking place during the plasma evolution responsible for such excitations like ions-electrons collisional recombination, where the observed species is with one lower positive charge. 17,36,37 As shown in Figure 5, the continuum emission was small FIG.…”

Sensing Signatures Mediated by Chemical Structure of Molecular Solids in Laser-Induced Plasmas

“…3 Particularly, a considerable number of investigations have been made on graphite plasmas to reveal the spatial and temporal distribution of different species ejected during ablation. [4][5][6][7] Studies on organic plasmas in various atmospheres 8 at a range of pressures, [9][10][11][12] using different laser wavelengths, 13 at diverse laser fluence regimes, have provided valuable information in the context of pulsed laser deposition, well known for its capabilities for film synthesis as well as for the assembling of novel materials such as single-walled carbon nanotubes. 14 Progress in laser ablation together with monitoring of optical emissions has emerged as a valuable method for characterization of laser-induced organic plasmas.…”