Multipulse photon echoes inLaF3:Pr3+

Multipulse photon echoes are observed from ${\mathrm{LaF}}_3$:${\mathrm{Pr}}^{3+}$ and are shown to be primarily stimulated echoes. The various contributions to the echoes were measured using a three-pulse photon-echo sequence that resolved the image of the echo generated by the first two pulses, and the echo generated by the second and third pulses and that of the first and third pulses from the stimulated echo. By use of a theoretical model of Shoemaker [in Laser and Coherence Spectroscopy, edited by J. I. Steinfeld (Plenum, New York, 1978)] and relaxation theory of Hu and Hartmann [Phys. Rev. B 9, 1 (1974)], the image echo contributions to the third echo is shown to be less than 10% of the total for the pulse widths and Rabi frequencies used in the measurements. As a result, multipulse photon echoes will find limited use in measuring coherence decay until very short high-intensity pulses are used to excite the echoes.