Theoretical model for double pulse laser-induced breakdown spectroscopy.
We present a simple theoretical model for the emission from double pulse laser-induced plasmas that was developed to better understand the processes and factors involved in enhancement of plasma emission. In this model, the plasma emission is directly proportional to the square of plasma density, its volume, and the fraction of second laser pulse absorbed through inverse bremsstrahlung absorption by the plasma plume of the first laser pulse. The electron-ion collision frequency determines the profile and location of the peak of emission enhancement with respect to the delay between the two lasers, whereas the amplitude of the enhancement is mainly dependent on the increase in the mass ablation rate after the second laser pulse. The effects of increase in temperature and in plasma volume after the second laser pulse are also discussed in light of this model.
Rai
Virendra N
VN
Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, India. vnrai@cat.ernet.in
Yueh
Fang Yu
FY
Singh
Jagdish P
JP