Propagation of nuclear polaritons through a two-target system: Effect of inversion of targets

Abstract

The propagation of nuclear polaritons through a scattering system composed of two spatially separated targets was studied. The stainless-steel targets were highly enriched in resonant 57 Fe nuclei and had different thicknesses, and, in addition, the resonance width of one target could be increased by cooling it to low temperatures. A nuclear polariton state was created in both targets almost instantly by a short flash of synchrotron radiation. The propagation of the polariton could be perturbed by a time-dependent Doppler shift of the resonance energy in one of the targets. The effect of inversion of the target sequence on the polariton propagation was in the focus of our investigations. It was shown both theoretically and experimentally that in general a two-target scattering system is not commutative.

Coherent Control of Nuclei and X-Rays

“…However, since the phase of a single photon is totally undefined, a method for measuring the magnetically modulated π phase shift is to be addressed. For the definition and the measurement of this π-phase shift of single photons, we refer to the echo technique using two nuclear targets [43,132,138] and demonstrate for the first time a magnetically induced nuclear exciton echo without any mechanical vibration of the targets. In the next section, we will see how this feasible echo two-target setup can also be used for photon storage involving a mere rotation of the hyperfine magnetic field by 180…”

“…A typical x-ray optics setup would require to let the π-modulated photon interfere with a part of the original pulse on a triple Laue interferometer [143,144]. We adopt here another approach, namely, the simple and elegant photon echo solution used in NFS experiments with SR [43,132,138,145,146] to allow the scattered photon to interfere with itself in the two-target setup presented in Fig. 4.11.…”

“…A reversible magnetic field B 1 is applied to target 1, and an irreversible B 2 is applied to target 2. The target response is determined by 26) and [13,132,146] 27) and the forward-scattered x-ray field is then given by [132] …”

“…As showed in Fig. 5.6 we consider a two-crystals system [43,129,132] and apply an external magnetic field to one of the crystals. All nuclei are assumed to equally populate | .…”

“…One nucleus may be excited by the recoilless photon absorption, but there is no way to know which one from the measurements if neither nuclear spin flip nor internal conversion occurs. This delocalized single nuclear excitation is called nuclear exciton [13] or nuclear polariton [132], and was independently introduced by Hannon & Trammell and Kagan & Afanas'ev [13]. In atomic physics, the same concept is called single photon superradiance or directed spontaneous emission [87].…”