Study of expansion of laser ablation plumes of Ga and GaN in various N2 atmospheres using stigmatic emission spectroscopy

The dynamics of expansion of laser ablation plumes of Ga and GaN in various N2 atmospheres is studied using stigmatic ultraviolet emission spectroscopy. This technique allows the simultaneous recording of the plume absolute emission intensities up to 4 cm above the target surface in the spectral range from 240 to 500 nm. At 250 nm, the spatial resolution of the system is ∼80 μm and its spectral resolving power is ∼40,000. The variations of the intensities and widths of selected lines as a function of laser wavelength, laser fluence and N2 ambient pressure are presented.