Investigation of the relaxation of excited states using a three-pulse photon echo

G. M. Ershov

Sven R. Hartmann

J. Keller, J.-L. Le Gouët

With a three-level configuration in ytterbium vapor, we have performed the first quantitative investigation of single excited-level scattering using a stimulated photon echo (three-pulse echo). We have studied the collisional relaxation of the echo signal by rare-gas perturbers and have derived a theoretical expression for the relaxation rate. Total elastic cross sections for collisions between $\mathrm{Yb}(6s6p^{3}P_{1}$) and Ne or Xe have been obtained.

A. Flusber, THOMAS W. MOSSBERG, Sven R. Hartmann

T. Takagahara

Nonlinear optical methods to determine the transverse relaxation constants of excitonic molecules making use of two-photon echo and a new type of excited state photon echo are proposed. The two-photon echo is a seventh order nonlinear effect at the lowest and one needs three pulses to observe it, while the excited state photon echo is a fifth order nonlinear effect and requires four pulses. In these nonlinear optical methods we can satisfy the phase matching condition rather easily due to the large dispersion of excitonic polaritons. We can determine directly the transverse relaxation constants associated with the excitonic molecule from the correlation trace of the two-photon echo and the excited state photon echo.

A. I. Alekseev, O. V. Zhemerdeev