Observation of Pumping Reaction in an Amine-Based All Gas-Phase Iodine Laser Medium

Gain measurement of all gas-phase iodine laser (AGIL) based on amine-based reactions is conducted. Three gaseous species, namely, NCl3, H, and HI are mixed in a glass tube, in which injection ports of each species are optimized using a numerical simulation code developed in our laboratory. The laser duct is attached downstream to the mixing tube, and a probe beam of 1315 nm passes at 23 cm downstream from the mixing point of H and HI. Hydrogen atoms are produced by the microwave discharge of the H2/He admixture. When NCl3 is not supplied, absorption by the 2P1/2–2P3/2 transition of iodine atoms is observed. When NCl3 is supplied, the absorption dip occasionally turns to the hump, which means that the energy transition from NCl(a1Δ) to iodine atoms results in population inversion. The observed small signal gain is 0.005%/cm. However, the reproducibility of the observed phenomenon is poor and presumably, some uncontrolled factor affects the gain evolution. To our knowledge, this is the first observation of a positive gain of the amine-based AGIL system.