Determination of kinetic energy distribution in a laser-ablated titanium plume by emission and laser-induced fluorescence spectroscopy

Pulsed laser deposition (PLD) of thin films has become a viable technique for a wide range of applications over the last few decades. As kinetic energy of the ablated plume is an important parameter in determining the quality of the film; consequently there is great interest in nonintrusive evaluation of the plume kinetic energy. Spectroscopic techniques such as optical time-of-flight (TOF) utilizes emission spectroscopy or laser-induced-fluorescence (LIF) and is an excellent method for this purpose since they offer temporal and spatial resolution as well as the capability of distinguishing different species. In this paper, the effects of laser fluence and background gas pressure on the kinetic energies of the ablated species are found by the optical time-of flight technique and by emission imaging. Laser-induced-fluorescence is employed for spectrally resolved imaging. The axial velocity of neutral titanium is found to be as high as 2X10(4) m/s. The distribution of species within the plume is also determined.