Influence of laser irradiance and helium ambient on the expansion of laser produced carbon plasma

摘要

The emission features of laser ablated carbon plasma plume generated in helium ambient have been investigated with time resolved plasma diagnostic technique. At lower irradiance levels only a slowly propagating C_2 component is seen. At higher irradiance levels, emission from C_2 shows a twin peak distribution in time. The present results also show that the helium ambient pressure and laser irradiance has opposite effects on the time of flight (TOF) profiles of C_2 species. A simple adiabatic expansion model appears to provide a good description of the plume range and this may prove useful for scaling deposition experiments in terms of pressure and laser irradiance.