Ultimate capabilities for compression of the waveform of a recoilless γ -ray photon into a pulse sequence in an optically deep vibrating resonant absorber

摘要

Recently, an exponentially decaying waveform (the time dependence of detection probability) of a M?ssbauer γ -ray photon was transformed into a regular sequence of short pulses in a sinusoidally vibrating recoilless resonant absorber [F. Vagizov, V. Antonov, Y. V. Radeonychev, R. N. Shakhmuratov, and O. Kocharovskaya, Coherent control of the waveforms of recoilless γ -photons, Nature (London) 508, 80 (2014)]. In the present paper, we show that the peak amplitude of the pulses can be considerably increased via joint adjustment of optical depth of the absorber and the initial phase of its vibration. This is due to reduction of the photoelectric absorption and maximizing the constructive temporal interference of spectral content of the single-photon wave packet in an optically deep absorber. The ultimate capabilities for transforming a waveform of a 14.4-keV photon from a ~(57)Co radioactive source into a regular train of pulses in a harmonically vibrating ~(57)Fe recoilless resonant absorber are discussed. We show that the shortest pulse duration, produced by this technique, is limited by the highest available vibration frequency of a piezoelectric transducer and at present can be as short as 7.7 ps. The maximum achievable detection probability of the transformed photon at the experimentally feasible conditions is more than two times higher than peak detection probability of the photon emitted by the source and nearly 5.5 times higher than obtained in the above reference.