The optical absorption coefficient of Ti:Al2
samples at 490 nm for the π polarization (E
) is found to be proportional to the concentration of Ti3+
ions, as determined by measurement of the paramagnetic moment as a function of temperature and magnetic field. The experimental data yield the value σ=(9.3±1.0)×10−20
for the absorption cross section of Ti3+
, the active ion in the tunable Ti:Al2
laser, at the peak of the laser pump band.