Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

EUV-FEL 励起由来のヘリウムイオンからの 164 nm 超蛍光の観測

ハリーズ ジェームズ, James Harries

Published Mar 23, 2018• 0 citations
OpenAlex

Abstract

We report the probable observation of superfluorescence at a wavelength of 164 nm from helium ions created and excited using pulses from the EUV free-electron laser at SACLA BL1. The emission is the second step of a superfluorescence cascade from excited 4p states. To our knowledge this is the shortest wavelength at which superfluoresence has ever been demonstrated. The high intensity of the emission and the narrow angular divergence strongly support the interpretation as superfluorescence, and numerical simulations will also be presented which support this.

Related papers

ヘリウムイオンの FEL 励起に伴う超蛍光、ヨーク超蛍光、自由誘 導減衰、四光波混合

ハリーズ ジェームズ, James Harries

We report the observation of superfluorescence at wavelengths of 469 nm, 164 nm and 30.4 nm from helium ions created and excited using pulses from the EUV free-electron laser at SACLA BL1. Experimental observations of intense, highly-directional emission (all 3 wavelengths) and a 1/(density) pulse delay dependence (469 nm emission), along with a detailed numerical simulation support our interpretations.

•Mar 17, 2019•0 citations

Extreme ultraviolet superfluorescence from helium ions

ハリーズ ジェームズ, James Harries

We report the observation of superfluorescence at wavelengths of 469 nm, 164 nm and 30.4 nm from helium ions created and excited using pulses from the EUV free-electron laser at SACLA BL1. The observations at 164 nm and 30.4 nm represent the first ever observations at such short wavelengths.

•Jun 6, 2019•0 citations

Superfluorescence, superradiance, and free-induction decay observed following the excitation of helium atoms and ions with FEL pulses from SACLA BL1

ハリーズ ジェームズ, ハリーズ ジェームズ

Using EUV pulses from SACLA BL1 free-electron laser, we have successfully observed superfluorescence at wavelengths of 469 nm and 164 nm from a dense sample of excited helium ions, created by (1+1)-photon ionisation/excitation. The results of related numerical simulations will also be reported.

•Sep 11, 2017•0 citations

Detailed study of superfluorescence at a wavelength of 469 nm from helium ionised and excited using free-electron laser pulses

ハリーズ ジェームズ, James Harries

We have studied in detail the emission of superfluorescence at a wavelength of 469 nm (4p→3s) from helium ions created and excited using free-electron laser pulses from SACLA’s BL1. In earlier work we observed superfluorescence at visible wavelengths in neutral helium [1-5]. To observe superfluorescence from helium ions we used a wavelength of 24.3 nm, resonant with the He + 1s→4p transition and sufficiently short to ionise neutral helium atoms. The density of excited He + ions created by this sequential 2-photon absorption was sufficient to allow for the development of superfluoresence.

•Oct 11, 2018•0 citations

Observation of superfluorescence at a wavelength of 164 nm from ‘highly’ - charged helium ions

ハリーズ ジェームズ, ハリーズ ジェームズ

Using EUV pulses from SACLA BL1 free-electron laser, we have successfully observed superfluorescence at wavelengths of 469 nm and 164 nm from a dense sample of excited helium ions, created by (1+1)-photon ionisation/excitation. The results of related numerical simulations will also be reported.

•Sep 8, 2017•0 citations

Time-resolved observation of superfluorescence at a wavelength of 164 nm from helium ions

James Robert Harries, Yoshiro Azuma, Arisa Iguchi +6 more

Abstract We report the results of an experiment to study the temporal properties of superfluorescence at a wavelength of 164 nm emitted from helium ions excited to either the 3p state or 4p state by pulses from a free-electron laser. The two different processes (direct 3p–2s superfluorescence; two-step cascade 4p–3s–2p or 4p–3d–2p superfluorescence) are compared to each other and to the results of numerical simulations.

Journal of Physics B Atomic Molecular and Optical Physics•Mar 11, 2026•0 citations
We report the probable observation of superfluorescence at a wavelength of 164 nm from helium ions created and excited using pulses from the EUV free-electron laser at SACLA BL1. The emission is the second step of a superfluorescence cascade from excited 4p states. To our knowledge this is the shortest wavelength at which superfluoresence has ever been demonstrated. The high intensity of the emission and the narrow angular divergence strongly support the interpretation as superfluorescence, and numerical simulations will also be presented which support this.
We have studied in detail the emission of superfluorescence at a wavelength of 469 nm (4p→3s) from helium ions created and excited using free-electron laser pulses from SACLA’s BL1. In earlier work we observed superfluorescence at visible wavelengths in neutral helium [1-5]. To observe superfluorescence from helium ions we used a wavelength of 24.3 nm, resonant with the He + 1s→4p transition and sufficiently short to ionise neutral helium atoms. The density of excited He + ions created by this sequential 2-photon absorption was sufficient to allow for the development of superfluoresence.