Abstract: In a system for isotope enrichment, a method and apparatus for separating atoms of one isotope type from an environment containing plural isotope types. Tunable lasers or laser systems are used to selectively pump atoms of the desired isotope to a metastable excited state several eV above the isotope atom ground state. A reduced ionization energy is then supplied to atoms of the metastable isotopes taking advantage of the longer lifetimes achieved. The resulting plasma created by ionizing atoms of the isotope in the metastable state is subjected to electromagnetic fields to separate atoms of the desired isotope.