Improved performance and rotational spectral characteristics of a doped helical TEA CO2laser

In this paper, we report significant improvement in laser energy, peak power, beam quality, and arc-free operating range of pressure in a helical TEA CO
2
laser using a small amount of additives with low ionization potentials. The increase in laser power was found to be considerably more than the corresponding increase in laser energy with the use of additives. In addition, we observed laser oscillation on many more rotational lines including the most dominant P(20) line than is normally observed in an undoped mixture. The relative energy on the P(20) line with respect to the total energy on the rest of the lines showed a maximal behavior with pressure in the range of 0.2-1.0 atm. This has been explained using a theoretical model which takes into account reduction in both the rotational relaxation time and the rise in laser gas temperature with the increase in gas pressure.