Time-resolved imaging and optical spectroscopy of plasma plumes during pulsed laser material deposition

We employ fast imaging photography and emission spectroscopy to study plasma plumes resulting from the 248-nm ablation of barium strontium titanate, and we utilize x-ray diffraction analysis and scanning electron microscopy to characterize the deposited thin films. Hydrodynamic plume analyses yield initial velocities of approximately 20 km/s, whereas spectral simulations of the Ba I lines between 739 and 770 nm yield temperatures of approximately 17000 K at early times in vacuum. Analyses of the Stark broadened Ba II lines at 614 and 649 nm reveal an electron number density of approximately 10(+18) cm(-3) near the surface. Several Pa of oxygen reduces these values while improving the film quality.