Color center creation in LiF crystals irradiated with Xe, Kr and N ions: Dependence on fluence and beam current density

Color centers and nanodefects in LiF crystals irradiated with 150MeV Kr ions

“…It was shown that the creation of F centers strongly depends on the ion beam current (nA/cm 2 ) or flux (ions/ cm 2 s). At high flux values the efficiency of color center creation increases, especially for complex F n centers [10,11]. This should result also in fluorine molecule clusters (nX 2 ) and stimulate the formation of nanoscale defects [7,12,13].…”

Material characterization and modification using helium lon microscopy : various examples

“…Due to the reduced concentration of H-centers that can recombine with F-centers, the concentration of F-centers is efficiently increased and we observe an enhancement of the IL signal. A similar effect of enhanced F-center creation was observed in the case of LiF [140,141]. Dislocations are also effective traps for H-centers [126,142] and are able to further enhance F-center formation.…”

“…When the current density increases, the events temporally overlap, and the processes that occur are not independent anymore. When the cascade events start to overlap, the high H-center concentration, combined with the high mobility of such centers, increases the probability for the formation of a Cl 2 molecule [108,[140][141][142]. The recombination rate between an F-center and Cl 2 is much smaller than that between F -H centers.…”

Multiple filamentation of femtosecond laser pulses

“…This is because the F 2 centers form via the aggregation of primary defects. At high irradiation doses, however, the concentration of these color centers reaches satu ration, due to different physical mechanisms [10]. In addition, the efficiency of fluorescence falls at high concentrations because of reabsorbtion by centers of different types.…”