Ts. Rose et al., CHARACTERIZATION AND CONTROL OF GAMMA-RADIATION AND PROTON-RADIATION EFFECTS ON THE PERFORMANCE OF ND-YAG AND ND-YLF LASERS, IEEE journal of quantum electronics, 31(9), 1995, pp. 1593-1602
The laser performance of Nd:YAG and Nd:YLF crystals longitudinally pum
ped at 800 nm was evaluated before and after exposure to Co-60 gamma r
ays and high energy (30-50 MeV) protons, Both forms of radiation creat
ed the same damage centers in the respective crystals, which reduced o
ptical output primarily by absorbing the laser emission. While the rad
iation induced loss at the lasing wavelength for high quality Nd:YAG r
eached a limiting value of similar to 0.015 cm(-1) at 100 krad exposur
e levels, the loss in Nd:YLF was significantly larger than in Nd:YAG f
or all comparable dosage levels, and did hot appear to have a limiting
value, Given the relatively short path lengths of the laser crystals
that were tested, the loss could be overcome for both materials under
pulse-pumped operation, demonstrating that certain Nd lasers can be ef
fectively radiation hard by design. Additionally, for the first time,
Cr3+ was codoped with Nd in YAG (with minimal Cr4+ formation) yielding
a high performance material with a significantly reduced in radiation
susceptibility.