A Study of the Neutral Atomic Iodine Laser

Details are given on the laser action in electronic transitions between the 5d and 6p levels of neutral atomic iodine. Experimental results show that the power output obtained using dc excitation can be improved by superimposing rf excitation on the discharge plasma. The electron temperature and density were measured and for the superimposed condition were found to be 1.0 x 10(5) K and 5.0 x 10(11)/cm(3), respectively. The spontaneous intensities of all the laser lines and their related transitions were measured. By combining these results with calculated Einstein A coefficients, numerical data were obtained on the population densities, pumping rates, radiative lifetimes, and gains of the helium-iodine laser lines. These results indicate that strong population inversions exist for the 5dJ = 7/2, 9/2 levels whose radiative relaxation directly to the ground state is forbidden. Multistep deexcitation processes are proposed to explain the characteristics of the laser lines.