| 1. |
- Escoto, Esmerando, et al.
(författare)
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Role of dispersion and compression ratio on the temporal contrast of SPM-broadened post-compressed pulses
- 2021
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Ingår i: 2021 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2021. - 9781665418768
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Konferensbidrag (refereegranskat)abstract
- Nonlinear pulse post-compression, mainly enabled by self-phase modulation (SPM), opens new avenues towards high peak power laser pulses at high average power while bypassing the need for a gain medium with large bandwidth. However, SPM-induced spectral broadening typically introduces spectral amplitude modulations as well as a chirp of third and higher orders, limiting the temporal contrast of the compressed pulse. While some recent works address this issue and discuss mitigation strategies [1] , [2] , not much attention has been devoted to the physical processes and limitations that determine the temporal contrast of post-compressed pulses. As novel compression techniques expand the achievable compression ratio [3] , it is increasingly important to fully understand the underlying pulse quality limitations. Here, we outline the role of two important characteristics - dispersion and compression ratio - on the temporal quality of post-compressed pulses. Using both numerical simulations as well as experimental tests employing a gas-filled multi-pass cell (MPC), we study the temporal contrast of post-compressed pulses over large compression-ratio and dispersion range. Using a 730 fs input pulse we were able to generate a 55 fs post-compressed pulse with up to 78% energy contained in the main compressed pulse (defined via the first local minima near the highest peak) against its picosecond background.
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| 2. |
- Escoto, Esmerando, et al.
(författare)
-
Temporal quality of post-compressed pulses at large compression factors
- 2022
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Ingår i: Journal of the Optical Society of America B: Optical Physics. - 0740-3224. ; 39:7, s. 1694-1702
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Tidskriftsartikel (refereegranskat)abstract
- Post-compression of ultra-short laser pulses via self-phase modulation is routinely employed for the generation of laser pulses with optical bandwidths reaching far beyond the laser gain limitations. Although high compression factors can be routinely achieved, the compressed pulses typically suffer from temporal quality degradation. We numerically and experimentally analyze the deterioration of different measures of temporal quality with increasing compression factor and show how appropriate dispersion management and cascading of the post-compression process can be employed to limit the impact of this effect. The demonstrated saturation of pulse quality degradation at large compression factors puts novel femtosecond laser architectures based on post-compressed picosecond or even nanosecond laser systems in sight.
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| 3. |
- Viotti, Anne Lise, et al.
(författare)
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Intra-Burst Pulse Characterization of a High-Power Post-Compressed Yb:YAG Laser at 100 kHz Repetition Rate
- 2021
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Ingår i: 2021 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2021. - 9781665418768
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Konferensbidrag (refereegranskat)abstract
- High-average power Ytterbium (Yb) laser systems are playing an increasingly important role in ultrafast science e.g. as pump lasers for optical parametric amplifiers or directly as ultrafast sources. The gain bandwidth of Yb limits the pulse duration to a few 100 fs up to about 1 ps. However, many applications, such as attosecond physics or X-ray Free Electron Laser (FEL) science, would greatly benefit from the combination of high average powers with much shorter pulses, achievable via post-compression. Nonlinear pulse post-compression of high-average power Yb lasers employing multi-pass cell (MPC) -based spectral broadening [1], [2] was recently implemented for two burst-mode pump-probe lasers at the FEL facility FLASH in Hamburg [3], [4]. For such lasers, precise characterization and control of intra-burst pulse dynamics is crucial as the post-compression process couples input pulse energy instabilities with important output pulse parameters such as spectrum, pulse length and temporal contrast. Here, we demonstrate 100 kHz intra-burst spectrum, phase and temporal contrast characterization of a Yb:YAG Innoslab burst-mode amplifier post-compressed in a gas-filled MPC. Our measurements reveal a stable broadened spectrum and compressed pulse duration within the flat part of the burst, yielding a relative energy content of about 80% in the main compressed fs pulse (250 fs window versus 4 ps background pedestal).
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| 4. |
- Viotti, Anne Lise, et al.
(författare)
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Intra-burst temporal pulse contrast of a high-power post-compressed picosecond Yb:YAG laser
- 2021
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Ingår i: Conference on Laser and Electro-Optics : Science and Innovations, CLEO:S and I 2021 - Science and Innovations, CLEO:S and I 2021. - 9781557528209
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Konferensbidrag (refereegranskat)abstract
- We report on pulse contrast characterization of the output of a gas-filled multi-pass cell employed for 20-fold compression of a high-power Yb:YAG laser. We demonstrate an energy content of 80% in the compressed fs pulse.
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| 5. |
- Viotti, Anne Lise, et al.
(författare)
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Temporal pulse quality of a Yb:YAG burst-mode laser post-compressed in a multi-pass cell
- 2021
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Ingår i: Optics Letters. - 0146-9592. ; 46:18, s. 4686-4689
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Tidskriftsartikel (refereegranskat)abstract
- Nonlinear pulse post-compression represents an efficient method for ultrashort, high-quality laser pulse production. The temporal pulse quality is, however, limited by amplitude and phase modulations intrinsic to post-compression. We here characterize in frequency and time domain with high dynamic range individual post-compressed pulses within laser bursts comprising 100-kHz-rate pulse trains. We spectrally broaden 730 fs, 3.2 mJ pulses from a Yb:YAG laser in a gas-filled multi-pass cell and post-compress them to 56 fs. The pulses exhibit a nearly constant energy content of 78% in the main peak over the burst plateau, which is close to the theoretical limit. Our results demonstrate attractive pulse characteristics, making multi-pass post-compressed lasers very applicable for pump–probe spectroscopy at, e.g., free-electron lasers or as efficient drivers for secondary frequency conversion stages.
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