Abstract
We measured in-situ temporal decay and the spatial distribution of the transmission of a Cr:YAG
saturable absorber in a passively Q-switched Nd:YAG laser by a scanning transmission focused laserbeam
method. An excited ion decay time of 4 μs and top hat (saturated) transmission distribution were
observed. By a theoretical fi tting for the transmission distributions, the ground state absorption cross
sections were found to be 1.0 × 10‒17 and 2.3 × 10‒19 cm2 for π and for σ -polarized light to the S4 local
symmetry axis of Cr4+ center. The excited-state absorption cross section was estimated to be
2.4 × 10‒18 cm2.
