Effect of prepulse laser wavelength on EUV emission from CO2 reheated laser-produced Sn plasma

We investigated the role of prepulse laser wavelength on extreme-ultraviolet (EUV) emission and ionic debris generation. A 6 ns Nd:YAG laser operating at 266 nm was used to generate a pre-plasma that was then reheated by a 35 ns CO2 laser pumping pulse at 10.6 mu m. At an ideal delay time, improvement in EUV conversion efficiency (CE) of up to 30 % was seen compared to the CE from the pumping pulse alone. It was also shown that the most probable Sn ion kinetic energies were reduced significantly with the use of a prepulse, however, ion fluence increased. These results were compared to those obtained using a 1064 nm prepulse.