Abstract

We have observed an accelerated decay of the photon-echo intensity of the ${}^4{A}_2-2\overline{A}\left({}^{2}E\right)$ transition of Cr³⁺ in ruby due to stimulated emission of phonons from $2\overline{A}\left({}^{2}E\right)$ to Ē(²E). The $2\overline{A}\left({}^{2}E\right)-\overline{E}\left({}^{2}E\right)$ phonon transition is inverted by an intense laser pulse exciting Cr³⁺ into $2\overline{A}\left({}^{2}E\right)$. In analogy with the case of an inverted optical transition, we can discern two types of decay after inversion of the $2\overline{A}\left({}^{2}E\right)-\overline{E}\left({}^{2}E\right)$ two-level system.

© 1990 Optical Society of America