Density and electron temperature of laser induced plasma — a comparison of different investigation methods

Density and temperature sensitive line ratios in plasmas generated by laser ablation

“…From this equation and the aforementioned values for T e (Al II͒, N e (Al III͒, and T e (Al III͒, we obtain N e (Al II͒ Ӎ2.7ϫ10 17 cm Ϫ3 using Knudtson's 13 value for T e (Al II) or N e (Al II) Ӎ1.8ϫ10 17 cm Ϫ3 if we use the Al II temperature found by Lenk. 14 These values are similar to the electron density reported Knudtson, 13 and differences can be easily accounted for taking into account that the experimental setups of Knudtson 13 and Lenk 14 were probably different, and that the determination of the line intensity ratio was very crude.…”

“…From the spectrum presented by Knudtson 13 we estimate that the Al III line ratio I(3602)/I(4481)Ӎ3.6. In a different experiment Lenk 14 derived an electron temperature of 1.1 eV ͑13 000 K͒ for Al II and 1.6 and eV ͑19 000 K͒ for Al III. Using this temperature for Al III and the value derived for I(3602)/I(4481), we find that N e Ӎ1.2ϫ10 17 cm Ϫ3 in the region of the plasma where Al III prevails.…”

Inherent instability investigation for low speed laser welding of aluminum using a single-mode fiber laser

“…Another group (Lenk et al, 1996) experimented with a Q-switched Nd:YAG laser, operating at power densities of 300 MW/cm 2 , determined electron temperatures of approximately 14,000 K and electron densities of 3 × 10 16 cm −3 , and concluded that they "are not high enough for significant absorption by inverse bremsstrahlung." There have been several other studies (Barthélemy et al, 2005;Lu et al, 1999;Knudtson et al, 1987) that have found electron temperatures ranging from 5000 to 15,000 K and electron densities up to the order of 10 18 cm −3 , all reaching the same conclusion, namely that IB absorption is not significant.…”

Characterization of Aluminum Laser Produced Plasma by Target Current Measurements

“…10) Less studied in the past years, the high voltages and large return currents have been observed on laser irradiated targets of sufficient high electrical conductivity, due to the electrical contact between plasma and target. [11][12][13][14] In ref. 15 the measured voltage pulses have heights and durations dependent on the size of the reaction chamber.…”