An experimental upper limit to the nonradiative relaxation time between the4T2and2T1states of ruby

An upper limit of 4 ns has been determined for the nonradiative relaxation times between the
⁴
T
2
and
²
T
1
states of ruby. This value was deduced from the rate of rise of the red
²
T
1
fluorescences from ruby crystals pumped by the second harmonic of a 1.06-μ laser.