1. |
2. |
3. |
4. |
5. |
6. |
7. |
8. Coherent soft X-ray pulses from an echo-enabled harmonic generation free-electron laserGiovanni De Ninno, Primož Rebernik Ribič, 2019, original scientific article Abstract: X-ray free-electron lasers (FELs), which amplify light emitted by a relativistic electron beam, are extending nonlinear optical techniques to shorter wavelengths, adding element specificity by exciting and probing electronic transitions from core levels. These techniques would benefit tremendously from having a stable FEL source, generating spectrally pure and wavelength-tunable pulses. We show that such requirements can be met by operating the FEL in the so-called echo-enabled harmonic generation (EEHG) configuration. Here, two external conventional lasers are used to precisely tailor the longitudinal phase space of the electron beam before emission of X-rays. We demonstrate high-gain EEHG lasing producing stable, intense, nearly fully coherent pulses at wavelengths as short as 5.9 nm (~211 eV) at the FERMI FEL user facility. Low sensitivity to electron-beam imperfections and observation of stable, narrow-band, coherent emission down to 2.6 nm (~474 eV) make the technique a prime candidate for generating laser-like pulses in the X-ray spectral region, opening the door to multidimensional coherent spectroscopies at short wavelengths.
Found in: ključnih besedah
Keywords: free electron laser, coherence, x-rays
Published: 07.05.2019; Views: 2605; Downloads: 0
 Fulltext (6,89 MB) |
9. A detailed investigation of single-photon laser enabled Auger decay in neonPrimož Rebernik Ribič, Giovanni De Ninno, 2019, original scientific article Abstract: Single-photon laser enabled Auger decay (spLEAD) is an electronic de-excitation process which was recently predicted and observed in Ne. We have investigated it using bichromatic phase-locked free electron laser radiation and extensive angle-resolved photoelectron measurements, supported by a detailed theoretical model. We first used separately the fundamental wavelength resonant with the Ne+ 2s–2p transition, 46.17 nm, and its second harmonic, 23.08 nm, then their phase-locked bichromatic combination. In the latter case the phase difference between the two wavelengths was scanned, and interference effects were observed, confirming that the spLEAD process was occurring. The detailed theoretical model we developed qualitatively predicts all observations: branching ratios between the final Auger states, their amplitudes of oscillation as a function of phase, the phase lag between the oscillations of different final states, and partial cancellation of the oscillations under certain conditions.
Found in: ključnih besedah
Summary of found: ...We have investigated it using bichromatic phase-locked free electron laser radiation and extensive angle-resolved photoelectron... ...laser enabled Auger decay (spLEAD) is an electronic de-excitation process which was recently predicted and...
Keywords: laser enabled Auger decay, free-electron lasers, neon
Published: 12.01.2020; Views: 2152; Downloads: 0
Fulltext (996,35 KB) |
10. Element selective probe of the ultra-fast magnetic response to an element selective excitation in Fe-Ni compounds using a two-color FEL sourceEugenio Ferrari, C. Spezzani, Franck Fortuna, Renaud Delaunay, Franck Vidal, Ivaylo Nikolov, Paolo Cinquegrana, B. Diviacco, David Gauthier, G. Penco, Primož Rebernik Ribič, Giovanni De Ninno, 2017, original scientific article Found in: ključnih besedah
Summary of found: ... free electron laser, two-color source, ultra-fast dynamics...
Keywords: free electron laser, two-color source, ultra-fast dynamics
Published: 13.01.2020; Views: 2404; Downloads: 8
This document has many files! More...
|
