It is possible to obtain uniform stable long‐pulse excitation (?100 &mgr;s) in gas mixtures involving highly electronegative constituents (SF6, CCl4, NF3, and I2). Such a system was used to investigate the atomic fluorine laser. In the hollow cathode, lasing on fluorine transitions in the doublet system lasted for up to 80 &mgr;s with no signs of the self‐termination as reported previously in positive‐column devices. The excitation process of the laser appears to depend heavily upon the fluorine donor utilized. For instance, a single‐step process is involved when NF3is used whereas a two‐step process is evident for SF6. The details will be discussed.