Enhanced performance of the iodine monofluoride (491 nm) laser

The impact of substituting HI for CF₃I as the iodine donor in the discharge-pumped iodine monofluoride (IF) laser at 491 nm has been investigated. More than an order of magnitude improvement in output pulse energy has been observed and is attributed to more efficient production of low-lying (v'<5) vibrational levels of the IF (D') ion pair state. Preliminary evidence indicates that vibrational excitation of HI (X¹Σ⁺ ) assists in the relaxation of the D' state population. The increased net small-signal gain of D'→A' (v'=0→v^") transitions in HI-containing gas mixtures has the effect of intensifying the 491-nm (0.15) bandhead relative to the lower gain transitions