where * represents an excited state, and Δ"E" is the small energy difference between the energy states of the two atoms, of the order of 0.05 eV, or 387 cm−1, which is supplied by kinetic energy. Excitation-energy transfer increases the population of the neon 4s2 and 5s2 levels manyfold. When the population of these two upper levels exceeds that of the corresponding lower level, 3p4, to which they are optically connected, population inversion is present. The medium becomes capable of amplifying light in a narrow band at 1.15 μm (corresponding to the 4s2 to 3p4 transition) and in a narrow band at 632.8 nm (corresponding to the 5s2 to 3p4 transition). The 3p4 level is efficiently emptied by fast radiative decay to the 3s state, eventually reaching the ground state.