Study the effect of fundamental and second harmonic wavelength on plasma parameters of emission magnesium lines in Nd: YAG laser

In this current study, we have studied the effect of laser energy and wavelength on heating the laser- ablated Mg plasma plume by using nanosecond Nd: YAG Laser. The creation of an ablated plasma plume was carried out by laser beam bombardment of a pure magnesium target using different laser energies 300-700 mJ with fundamental (1064 nm) and second (532 nm) harmonic laser. The Boltzmann plot method was used to measure the electron temperature of the Mg plasma; we noticed that the electron temperature values have increased with an increase in laser energy; these values around 3400 to 14013 K and 3106 to 7182 K for both modes of laser, respectively. On the other hand, the electron density in the plasma plume has been estimated through the Stark-broadening profiles from spectral lines of the isolated natural magnesium lines (Mg I) at 333.6 nm emitted by the plasma induced by two modes of Nd: YAG laser via 3s3p 3P2 → 3s5s3S1 transition, we found out that the values of density ranged from 0.86 to 2.1x1018 cm−3 at Lλ 1064 nm and from 1.5 to 3.2x1018 cm-3 at Lλ 532 nm at the studied laser irradiance ranged from 2.1-4.8x108 W/cm2. These findings can be understood due to the difference of inverse bremsstrahlung (IB) radiation and the mass ablation rate with the laser parameters studied.