Abstract
We report on a low-debris, efficient extreme ultraviolet (EUV) source by use of a liquid micro-target containing low-concentration tin oxide nano-particles. Conversion efficiency from a laser pulse energy to an in-band EUV energy (2% bandwidth (BW) and 2πIsr solid angle) depended on various experimental parameters, such as tin oxide concentration, laser intensity, and pulse separation time between dual laser pulses. By using a low concentration (6%) colloidal target together with dual laser pulses under the optimum separation time, we observed the EUV conversion efficiency of 1.2% with undetectable debris.
