Physical review. B, Condensed matter
Accumulated photon echo in ruby and alexandrite
M.H.F. Overwijk, P. J. Rump, J. I. Dijkhuis, H. W. de Wijn
Abstract
The technique of picosecond accumulated photon echo is applied to 700-at. ppm ruby and 2000-at. ppm alexandrite. The decay of the photon-echo intensity versus the probe-pulse delay displays a beat. A detailed analysis on the basis of Bloch equations shows that the beat frequency is associated with the zero-field splitting of the $^{4}$${\mathit{A}}_{2}$ ground state, and that its phase and amplitude are determined by the amount of population communication within this state. Precise values for the spontaneous decay time of 2A\ifmmode\bar\else\textasciimacron\fi{}${(}^{2}$E) and the $^{4}$${\mathit{A}}_{2}$ zero-field splitting are derived.