Low-density tin targets for efficient extreme ultraviolet light emission from laser-produced plasmas

Influence of initial density of tin (Sn) targets has been quantitatively investigated for efficient extreme ultraviolet light emission from laser-produced plasmas. With a decrease in the initial density, conversion efficiency (CE) from incident laser energy to output 13.5 nm light energy in a 2% bandwidth increases; 2.2% of the peak CE was attained with use of 7% low-density SnO2 targets (0.49 g/cm(3)) irradiated with a Nd:YAG laser, of which wavelength, pulse duration, and intensity are, respectively, 1.064 mu m, 10 ns, and 5x10(10) W/cm(2). The peak CE is 1.7 times higher than that obtained with the use of solid density Sn targets. Experimental results may be attributed to the influence of the initial density and/or microstructure of the targets on expansion dynamics of the plasmas.