TY - JOUR
T1 - Spontaneous and stimulated radiative emission of modulated free-electron quantum wavepackets—semiclassical analysis
AU - Pan, Yiming
AU - Gover, Avraham
N1 - Publisher Copyright:
© 2018 The Author(s). Published by IOP Publishing Ltd.
PY - 2018/11
Y1 - 2018/11
N2 - Here we present a semiclassical analysis of spontaneous and stimulated radiative emission from unmodulated and optically-modulated free-electron quantum wavepackets. We show that the radiative emission/absorption and corresponding deceleration/acceleration of the wavepackets depend on the controllable ‘history-dependent’ wavepacket size. The characteristics of the radiative interaction when the wavepacket size (duration) is short relative to the radiation wavelength, are close to the predictions of the classical point-particle modelling. On the other hand, in the long-sized wavepacket limit, the interaction is quantum-mechanical, and it diminishes exponentially at high frequency. We exemplify these effects through the scheme of Smith-Purcell radiation, and demonstrate that if the wavepacket is optically-modulated and periodically-bunched, it exhibits finite radiative emission at harmonics of the modulation frequency beyond the limit of high-frequency cutoff. Besides, the radiation analysis is further extended to the cases of superradiant emission from a beam of phase-correlated modulated electron wavepackets. The features of the wavepacket-dependent radiative emission explain the classical-to-quantum transition, and indicate a way for measuring the quantum electron wavepacket size. This suggests a new direction for exploring light–matter interaction.
AB - Here we present a semiclassical analysis of spontaneous and stimulated radiative emission from unmodulated and optically-modulated free-electron quantum wavepackets. We show that the radiative emission/absorption and corresponding deceleration/acceleration of the wavepackets depend on the controllable ‘history-dependent’ wavepacket size. The characteristics of the radiative interaction when the wavepacket size (duration) is short relative to the radiation wavelength, are close to the predictions of the classical point-particle modelling. On the other hand, in the long-sized wavepacket limit, the interaction is quantum-mechanical, and it diminishes exponentially at high frequency. We exemplify these effects through the scheme of Smith-Purcell radiation, and demonstrate that if the wavepacket is optically-modulated and periodically-bunched, it exhibits finite radiative emission at harmonics of the modulation frequency beyond the limit of high-frequency cutoff. Besides, the radiation analysis is further extended to the cases of superradiant emission from a beam of phase-correlated modulated electron wavepackets. The features of the wavepacket-dependent radiative emission explain the classical-to-quantum transition, and indicate a way for measuring the quantum electron wavepacket size. This suggests a new direction for exploring light–matter interaction.
KW - Light
KW - Matter interaction
KW - Radiative emission
KW - Wavepacket-dependent radiative emission
UR - http://www.scopus.com/inward/record.url?scp=85065850228&partnerID=8YFLogxK
U2 - 10.1088/2399-6528/aae2ec
DO - 10.1088/2399-6528/aae2ec
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AN - SCOPUS:85065850228
SN - 2399-6528
VL - 2
JO - Journal of Physics Communications
JF - Journal of Physics Communications
IS - 11
M1 - 115026
ER -