On the lack of influence of disorder in Cr3+-doped LiSr0.8Ca0.2AlF6

Optical and electron spin resonance spectroscopies have been used to investigate the thermal stability of lasers based on Cr3+:LiSr0.8Ca0.2AlF6, a material in which the onset of critically inhibiting nonradiative decay at temperatures below 300 K might be expected based on results from other Cr3+-activated disordered gain media. The influence of disorder on the Cr3+ environment is shown to be very small in LiSr0.8Ca0.2AlF6 so that the T24→A24 fluorescence transition is not broadened relative to that in LiSrAlF6 and the onset of significant nonradiative decay is also held above room temperature.