| 1. |
- Dombi, Peter, et al.
(author)
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Conversion of chirp in fiber compression
- 2014
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In: Optics Letters. - : Optical Society of America. - 0146-9592 .- 1539-4794. ; 39:8, s. 2232-2235
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Journal article (peer-reviewed)abstract
- Focusing positively chirped femtosecond pulses into nonlinear fibers provides significant spectral broadening and compression at higher pulse energies than achievable conventionally because self-focusing and damage are avoided. Here, we investigate the transfer of input to output chirp in such an arrangement. Our measurements show that the group delay dispersion of the output pulse, originating from the nonlinearities, is considerably reduced as compared to the initial value, by about a factor of 10. The mechanism of chirp reduction is understood by an interplay of self-phase modulation with initial chirp within the fiber. A simple model calculation based on this picture yields satisfactory agreement with the observations and predicts significant chirp reduction for input pulses up to the μJ regime. In practice, the reduction of chirp observed here allows for compressing the spectrally broadened intense pulses by ultrabroadband dispersive multilayer mirrors of quite moderate dispersion.
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| 2. |
- Charalambidis, Dimitris, et al.
(author)
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The extreme light infrastructure—attosecond light pulse source (ELI-ALPS) project
- 2017. - 9783319648392
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In: Springer Series in Chemical Physics. - Cham : Springer International Publishing. - 0172-6218. ; :9783319648392, s. 181-218
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Book chapter (peer-reviewed)abstract
- Globally, large international research infrastructures have over many decades promoted excellence in science and technology. Aligned with the international practice, the Europe Strategy Forum for Research Infrastructures (ESFRI) has developed and keeps updating a roadmap for research infrastructures. The Extreme Light Infrastructure (ELI) is one of the two large scale Laser Research Infrastructures (RI) proposed in the ESFRI Roadmap published in 2006. ELI aims to provide access to some of the most intense world-wide lasers for the international scientific user community, as well as secondary radiation and particle sources driven by them, offering to the users new interdisciplinary research opportunities. ELI is currently implemented as a distributed infrastructure in three pillars: ELI-Beamlines (ELI-BL) in Dolní Břežany, Czech Republic, ELI-Attosecond Light Pulse Source (ELI-ALPS) in Szeged, Hungary and ELI-Nuclear Physics (ELI-NP) in Magurele, Romania. This chapter is devoted to introduce the Hungarian pillar, ELI-ALPS, which will be operational in Szeged in 2018, with the primary mission to provide to the users the highest laboratory spatiotemporal resolution and a secondary mission to contribute to the technological development towards 200 petawatt (PW) lasers for high-field science, which is the ultimate goal of the ELI project. The chapter includes descriptions of the primary and secondary sources, while emphasis is given to selected examples of the scientific case of ELI-ALPS, presenting unique access offered by the technologies to be hosted in the infrastructure.
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| 3. |
- Dombi, Péter, et al.
(author)
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Strong-field nano-optics
- 2020
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In: Reviews of Modern Physics. - 0034-6861. ; 92:2
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Journal article (peer-reviewed)abstract
- The present status and development of strong-field nano-optics, an emerging field of nonlinear optics, is discussed. A nonperturbative regime of light-matter interactions is reached when the amplitude of the external electromagnetic fields that are driving a material approach or exceed the field strengths that bind the electrons inside the medium. In this strong-field regime, light-matter interactions depend on the amplitude and phase of the field, rather than its intensity, as in more conventional perturbative nonlinear optics. Traditionally such strong-field interactions have been intensely investigated in atomic and molecular systems, and this has resulted in the generation of high-harmonic radiation and laid the foundations for contemporary attosecond science. Over the past decade, however, a new field of research has emerged, the study of strong-field interactions in solid-state nanostructures. By using nanostructures, specifically those made out of metals, external electromagnetic fields can be localized on length scales of just a few nanometers, resulting in signficantly enhanced field amplitudes that can exceed those of the external field by orders of magnitude in the vicinity of the nanostructures. This leads not only to dramatic enhancements of perturbative nonlinear optical effects but also to significantly increased photoelectron yields. It resulted in a wealth of new phenomena in laser-solid interactions that have been discovered in recent years. These include the observation of above-threshold photoemission from single nanostructures, effects of the carrier-envelope phase on the photoelectron emission yield from metallic nanostructures, and strong-field acceleration of electrons in optical near fields on subcycle timescales. The current state of the art of this field is reviewed, and several scientific applications that have already emerged from the fundamental discoveries are discussed. These include, among others, the coherent control of localized electromagnetic fields at the surface of solid-state nanostructures and of free-electron wave packets by such optical near fields, resulting in the creation of attosecond electron bunches, the coherent control of photocurrents on nanometer length and femtosecond timescales by the electric field of a laser pulse, and the development of new types of ultrafast electron microscopes with unprecedented spatial, temporal, and energy resolution. The review concludes by highlighting possible future developments, discussing emerging topics in photoemission and potential strong-field nanophotonic devices, and giving perspectives for coherent ultrafast microscopy techniques. More generally, it is shown that the synergy between ultrafast science, plasmonics, and strong-field physics holds promise for pioneering scientific discoveries in the upcoming years.
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