Spectroscopy of laser-induced carbon plasma with nanosecond time resolution

Abstract

Emission spectra in the visible spectral range generated by a Nd:YAG laser shining on graphite targets were taken with timeaveraging and time resolution. The analyses of the components and temperature of the plasma components were performed in helium environment using the LIBS (Laser Induced Breakdown Spectroscopy) technique.The vibration-rotation temperature of the C 2 radical in the plasma initiates around 8000 K and drops exponentially with time. The rate coefficient of the exponential emission decay is 0.0018 ns −1 . Thus, the expected lifetime of the C 2 Swan emission under our experimental conditions is 555 ns.In addition to C 2 , singly and doubly ionized carbon, and in the first phase of the plasma, a continuum electron radiation was also observed.

Time- and space-resolved spectroscopic characterization of a laser carbon plasma plume in an argon background

“…Using a combination of LIF imaging and visible spectroscopy, they identified C 2 and C 3 molecular emission, and established that C 2 emission was enhanced in the central part of the expanding plasma plume, and near the target surface. A fluence of 1 J cm −2 was used by Nagy et al [21] to study the time evolution of the C 2 emission in helium as background gas at 50 Torr pressure. The vibrational-rotational temperature of the C 2 molecules was estimated to be around 0.7 eV, and the lifetime of the C 2 emission was of the order of 550 ns.…”