Halogen hydride lasers with vibrational energy transfer from metastable diatomic molecules

The possibiliy of obtaining efficient coherent emission due to vibrational–rotational transitions in the halogen hydrides HF, DF, HCl, DCl, HBr, and DBr during vibrational energy transfer from slowly relaxing (metastable) diatomic molecules of H₂, HD, D₂, N₂, and CO is demonstrated theoretically. It is proposed that the metastable molecules be excited by electrical preionization. A detailed analysis is made of an H₂+HF+Ar system and the influence of the main factors determining the laser efficiency is identified: radiation spectrum (number of rotational sublevel J), initial gas temperature, proportions of the components, and specific energy input. An estimate is made of the opimal value of e/P (~3V·cm^–1·Torr ^–1). It is concluded that under optimal conditions the efficiency of these lasers may reach 40–50% for H₂+HF, HD+HCl, and D₂+HBr systems, and 50–70% for N₂+DBr and CO+DBr systems without the active medium being cooled.