Anisotropy of resonant absorption of high-frequency 0.87 X 1012 Hz phonons in the excited state of 3 + ions in ruby
Kaplyanskii A.A. , Basun S.A. , Rachin V.A., Titov R.A.
The dependence of the cross section of 0.87X 1012 Hz phonon absorption, in the transition Ё—>2A in the excited state of Cr3+ ions, on the propagation direction and on the phonon polarization is determined by optical detection of thermal pulses in ruby. The observations agree with the group-theoretical selection rules.