Efficient positronium excitation by two laser pulses for antihydrogen production

Antihydrogen production by charge exchange reaction between Positronium atoms and antiprotons requires an efficient excitation of Positronium atoms possibly up to a well defined Rydberg level. A two–step laser light excitation, the first from ground to n = 3 and the second from this level to a n-Rydberg level, is discussed both from the physical and technological point of view. In this study it is assumed that a Ps cloud is produced by positrons hitting a porous silica target, in presence of a guiding magnetic field. The calculation of the transition probability with substantially incoherent laser pulses shows a 30 % population deposition in high-n states.