Visible spectrum absorption cross section of Cr3+in the2E state of pink ruby

Absorption cross sections of Cr
³⁺
in the metastable
²
E states of pink ruby (0.05 percent Cr
2
O
3
) have been measured for
E \perp C
between 4000 Å and 7000 Å at 297°K and 115°K. Both 0 degree and 90 degree ruby rods were measured in a flash absorption apparatus having a spectral resolution of 50 Å. The broad excited state absorption bands centered at 5600 Å appear to correlate with the positions of
²
T
1
(
³
T
1
) level, while the narrow band centered at 4540 Å correlates well with the predicted
²
A
2
(
¹
E
) level. The effect of excited state absorption on laser operation is discussed in this paper.