exceed 100 nm the number of atoms in a metallic particle can be for example in a range from 1 to 100 the total number of heavy noble gas atoms in the heavy noble gas cluster 20 can be greater than a total number of the atoms in all metallic particles 30 by a factor of at least ten in one embodiment the total number of heavy noble gas atoms in the heavy noble gas cluster 20 can be greater than a total number of the atoms in all metallic particles 30 by a factor of at least one hundred in another embodiment the total number of heavy noble gas atoms in the heavy noble gas cluster 20 can be greater than a total number of the atoms in all metallic particles 30 by a factor of at least one thousand the metallic element within the metallic particles 30 can be any metallic element that can be excited to generate a plasma under irradiation by a laser beam the metallic element within the metallic particles 30 can be a transition metal element a lanthanide element an actinide element al ga in tl sn pb or bi in one embodiment the metallic element can be tin.