Laser discharge in a high-pressure jet of heavy noble gas: Expansion of emitting volume promises an efficient source of EUV light for lithography

A discharge with multiply charged ions of a noble gas supported by a powerful infrared laser in a high-pressure jet is considered as a source of extreme ultraviolet (EUV) light radiation in particular narrow bands demanded by next-generation lithography. In a proof-of-principle experiment in krypton, the EUV-emitting region is visualized using a dedicated EUV microscope. Measurements support a basic model of underlying physics that involves expansion of the emitting plasma outside the laser focus. In simulations, we show that using the xenon jet, more optimal for EUV emission, may provide an efficiency competitive to the best commercial EUV sources for lithography.