Method and arrangement for the efficient generation of short-wavelength radiation based on a laser-generated plasma

A method for the efficient generation of intensive short-wavelength radiation based on a laser-generated plasma comprising the steps of:

• directing at least one laser to a near-solid-density target located in a vacuum chamber;
• generating a prepulse for reducing the target density and a main pulse for avalanche ionization and for generation of a hot, radiation-emitting plasma, said prepulse and main pulse being generated successively;
• said prepulse being a first prepulse which is followed by at least a second prepulse which generates free electrons in the target by multiphoton ionization after a virtually complete recombination of free electrons generated by the first prepulse has taken place due to a long-lasting expansion of the target for reducing the target density;
• and
• directing the main pulse of a gas laser with a low critical electron density typical for its wavelength and a focus diameter which is adapted to the target diameter (DV) that is increased by the prepulses to the target immediately after the second prepulse when the second prepulse in the expanded target, whose ion density corresponds to the critical electron density of the gas laser taking into account the average ionization level of the target needed for the efficient generation of EUV radiation, has created enough free electrons so that an efficient avalanche ionization is triggered by the main pulse of the gas laser until reaching the ionization level of the target required for the desired radiation emission of the plasma.