W. Potzel et al., Investigation of radiative coupling and of enlarged decay rates of nuclearoscillators - art. no. 043810, PHYS REV A, 6304(4), 2001, pp. 3810
The nuclear forward scattering of synchrotron radiation (SR) of two spatial
ly separated stainless-steel foils has been investigated. Immediately after
the SR pulse a nuclear exciton extending over both targets is formed, whic
h then decays under the influence of radiative coupling of the nuclear osci
llators both within and between the targets. Cooling one target to low temp
eratures causes the Mossbauer linewidth to increase by inhomogeneous broade
ning. which leads to a rapid dephasing of the nuclear oscillators of this s
ystem. In general, the influence of the radiation field of the upstream osc
illators on the oscillators of the downstream target causes the latter to r
adiate at a high decay rate (steep slope) at early times. Surprisingly, for
the combined targets, the initial decay can be less steep than that of the
inhomogeneously broadened sample alone if this broadening is sufficiently
large. In addition, when the upstream oscillators are broadened in energy t
hey may cause the downstream oscillators to emit only very little intensity
at late times. In the experiments, this influence on the downstream sample
was changed by varying the inhomogeneous resonance broadening and the reso
nance frequencies of the targets. Drastic changes of the time evolution of
the nuclear forward scattering were observed, which are discussed within th
e dynamical theory.