Laser ablation of lanthanum phosphate for pulsed laser deposition

Abstract

Abstract A theoretical model has been used to simulate pulsed laser ablation of Lanthanum Phosphate (LaPO4) by nanosecond Nd:YAG laser irradiation. Material ablation rate per laser pulse was experimentally measured as a function of average incident laser fluence up to 12J/cm2. Calculations were performed by solving the heat conduction equation by an explicit finite‐difference technique to generate time evolution of temperature distribution, melt depth and ablation rate from the target during and after irradiation with a nanosecond laser pulse. Good agreement between our experimental and calculated ablation rates validates our theoretical model. The calculated maximum surface temperature of the LaPO4 target indicated that for laser fluence levels, up to 20J/cm2 material ejection from LaPO4 target is expected to occur via normal boiling and evaporation successfully avoiding explosive boiling. Our calculations confirm that operating with laser fluence at near ablation threshold levels for LaPO4 also restricts dissociation of the LaPO4 target to oxides with loss of gaseous products. Therefore, our study of pulsed laser ablation of LaPO4 target helps in making judicious selection of laser parameters for Pulsed Laser Deposition (PLD) of LaPO4 coatings and films of desired stoichiometric purity and homogeneity, while successfully ensuring phase stability of the target.

Keywords

• (LaPO4)
• lanthanum phosphate
• laser ablation
• pulsed laser deposition