Experimental and theoretical study of a CW D2-HCl energy transfer laser

An electric-discharge D2-HCl energy-transfer laser is described in which D2 is vibrationally excited in a discharge and then mixed with cold HCl in a supersonic expansion in order to provide population inversion between HCl vibrational bands. Detailed analysis of the HCl infrared fluorescence shows that the HCl vibrational temperature is about 2250-2300 K between levels 2 and 1. Theoretical modeling taking into account the discharge properties predicts a HCl vibrational temperature of about 2100-2300 K, in agreement with the experimental value. However, modeling also shows that the strong deactivation of the excited HCl molecules by the D atoms generated in the discharge prevents population inversion between the high vibrational levels. Thus the predicted amplification coefficients are very low, far from laser threshold.