Spatial characteristics of vacuum UV emission from laser-induced plumes in air

An effective method of discriminating against the strong background continuum emission in laser-induced breakdown spectroscopy (LIBS) experiments is to exploit the space dependency of laser-produced plasma emission. This is particularly essential in the VUV regime, where time-gated detectors become both technically and economically unfeasible. In the present work, a space-resolved time-integrated emission spectroscopic technique was employed to investigate the axial emission evolution of carbon ions within the 0-5 mm range from the target surface. The results are supported by measurements of the plasma's electron density and temperature in order to understand physical processes responsible for the spatial behaviour and characteristics of VUV radiation during the course of LIBS experiments on a steel target. The results obtained in the present study complement those produced using spectral lines lying in the UV-visible spectral regions.