The laser transition in neon at 6328 å is doppler broadened by the thermal motion of the atoms at a gas temperature of ~300oc (assume pure ne20). (volume = 1 cm3.) (a) what is the full width at half maximum of the transition? (ans. 1.81 ghz.) (b) suppose that a he: ne laser tube is placed inside a cavity 1 m long. how many temo. o.q modes are within ±δv/2 of the line center? (ans. 12.) (c) the energy of the upper state, 3 s2, is 166,658.484 cm-1 above the ground state. express the upper-and lower-state energies in ev. what is the quantum efficiency of this laser? (d) find the stimulated emission cross section given that a21 = 6.56 x 107 sec-1. (e) if the density of excited neon atoms in state i (j1 = 2) is 1010 cm-3, how many excited atoms in state 2 (j2 = 1) are required to establish a small-signal gain coefficient of 5%/m?