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Giant counter-rotating oscillations on the attosecond timescale

Bruhnke, Jakob Nicolai LU orcid ; Olofsson, Edvin LU ; Stenquist, Axel LU and Dahlström, Jan Marcus LU (2025) In Physical Review Research 7(4).
Abstract

We predict an unexplored type of ultrastrong coupling between atoms and intense ultraviolet light that leads to giant population oscillations on the attosecond timescale. These counter-rotating oscillations stem from the interference of energy-conserving and nonconserving photon absorption and emission processes via Rydberg states. They can be of similar amplitude as the elementary femtosecond Rabi oscillations between the two strongly coupled states. The effect, which is beyond the two-level atom, is nonreciprocal: It only affects the excited state, while the ground state is unaffected. We propose that two-photon Rabi oscillations (1s2-1s3d) in helium are suitable for the generation of this type of ultrastrong coupling with realistic... (More)

We predict an unexplored type of ultrastrong coupling between atoms and intense ultraviolet light that leads to giant population oscillations on the attosecond timescale. These counter-rotating oscillations stem from the interference of energy-conserving and nonconserving photon absorption and emission processes via Rydberg states. They can be of similar amplitude as the elementary femtosecond Rabi oscillations between the two strongly coupled states. The effect, which is beyond the two-level atom, is nonreciprocal: It only affects the excited state, while the ground state is unaffected. We propose that two-photon Rabi oscillations (1s2-1s3d) in helium are suitable for the generation of this type of ultrastrong coupling with realistic pulses. We use a combination of Floquet theory and effective Hamiltonian theory to test our predictions against ab initio simulations.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review Research
volume
7
issue
4
article number
L042019
publisher
American Physical Society
external identifiers
  • scopus:105022732160
ISSN
2643-1564
DOI
10.1103/jx8n-775g
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 authors.
id
e8fc4f66-ae33-4cd8-8ce5-b04274121feb
date added to LUP
2025-12-04 09:51:10
date last changed
2025-12-05 08:04:39
@article{e8fc4f66-ae33-4cd8-8ce5-b04274121feb,
  abstract     = {{<p>We predict an unexplored type of ultrastrong coupling between atoms and intense ultraviolet light that leads to giant population oscillations on the attosecond timescale. These counter-rotating oscillations stem from the interference of energy-conserving and nonconserving photon absorption and emission processes via Rydberg states. They can be of similar amplitude as the elementary femtosecond Rabi oscillations between the two strongly coupled states. The effect, which is beyond the two-level atom, is nonreciprocal: It only affects the excited state, while the ground state is unaffected. We propose that two-photon Rabi oscillations (1s2-1s3d) in helium are suitable for the generation of this type of ultrastrong coupling with realistic pulses. We use a combination of Floquet theory and effective Hamiltonian theory to test our predictions against ab initio simulations.</p>}},
  author       = {{Bruhnke, Jakob Nicolai and Olofsson, Edvin and Stenquist, Axel and Dahlström, Jan Marcus}},
  issn         = {{2643-1564}},
  language     = {{eng}},
  number       = {{4}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review Research}},
  title        = {{Giant counter-rotating oscillations on the attosecond timescale}},
  url          = {{http://dx.doi.org/10.1103/jx8n-775g}},
  doi          = {{10.1103/jx8n-775g}},
  volume       = {{7}},
  year         = {{2025}},
}