TY - JOUR
T1 - Light emission by free electrons in photonic time-crystals
AU - Dikopoltsev, Alex
AU - Sharabi, Yonatan
AU - Lyubarov, Mark
AU - Lumer, Yaakov
AU - Tsesses, Shai
AU - Lustig, Eran
AU - Kaminer, Ido
AU - Segev, Mordechai
N1 - Funding Information: ACKNOWLEDGMENTS. This work was partially funded by the US Air Force Office of Scientific Research, which supported our research on topological photonics, through which we came up with the ideas of PTCs. Publisher Copyright: © 2022 National Academy of Sciences. All rights reserved. Copyright © 2022 the Author(s). Published by PNAS.
PY - 2022/2/7
Y1 - 2022/2/7
N2 - Photonic time-crystals (PTCs) are spatially homogeneous media whose electromagnetic susceptibility varies periodically in time, causing temporal reflections and refractions for any wave propagating within the medium. The time-reflected and time-refracted waves interfere, giving rise to Floquet modes with momentum bands separated by momentum gaps (rather than energy bands and energy gaps, as in photonic crystals). Here, we present a study on the emission of radiation by free electrons in PTCs. We show that a free electron moving in a PTC spontaneously emits radiation, and when associated with momentum-gap modes, the electron emission process is exponentially amplified by the modulation of the refractive index. Moreover, under strong electron-photon coupling, the quantum formulation reveals that the spontaneous emission into the PTC bandgap experiences destructive quantum interference with the emission of the electron into the PTC band modes, leading to suppression of the interdependent emission. Free-electron physics in PTCs offers a platform for studying a plethora of exciting phenomena, such as radiating dipoles moving at relativistic speeds and highly efficient quantum interactions with free electrons.
AB - Photonic time-crystals (PTCs) are spatially homogeneous media whose electromagnetic susceptibility varies periodically in time, causing temporal reflections and refractions for any wave propagating within the medium. The time-reflected and time-refracted waves interfere, giving rise to Floquet modes with momentum bands separated by momentum gaps (rather than energy bands and energy gaps, as in photonic crystals). Here, we present a study on the emission of radiation by free electrons in PTCs. We show that a free electron moving in a PTC spontaneously emits radiation, and when associated with momentum-gap modes, the electron emission process is exponentially amplified by the modulation of the refractive index. Moreover, under strong electron-photon coupling, the quantum formulation reveals that the spontaneous emission into the PTC bandgap experiences destructive quantum interference with the emission of the electron into the PTC band modes, leading to suppression of the interdependent emission. Free-electron physics in PTCs offers a platform for studying a plethora of exciting phenomena, such as radiating dipoles moving at relativistic speeds and highly efficient quantum interactions with free electrons.
KW - Lasers
KW - Photonic crystals
KW - Photonics
KW - Ultrafast optics
UR - https://www.scopus.com/pages/publications/85124290210
U2 - 10.1073/pnas.2119705119
DO - 10.1073/pnas.2119705119
M3 - Article
C2 - 35131857
SN - 0027-8424
VL - 119
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 6
M1 - e2119705119
ER -