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Author: Nagy, Tamas × Subject: Nonlinear optics ×

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    High-energy few-cycle pulses: post-compression techniques
    (Abingdon : Taylor & Francis Group, 2021) Nagy, Tamas; Simon, Peter; Veisz, Laszlo
    Contemporary ultrafast science requires reliable sources of high-energy few-cycle light pulses. Currently two methods are capable of generating such pulses: post compression of short laser pulses and optical parametric chirped-pulse amplification (OPCPA). Here we give a comprehensive overview on the post-compression technology based on optical Kerr-effect or ionization, with particular emphasis on energy and power scaling. Relevant types of post compression techniques are discussed including free propagation in bulk materials, multiple-plate continuum generation, multi-pass cells, filaments, photonic-crystal fibers, hollow-core fibers and self-compression techniques. We provide a short theoretical overview of the physics as well as an in-depth description of existing experimental realizations of post compression, especially those that can provide few-cycle pulse duration with mJ-scale pulse energy. The achieved experimental performances of these methods are compared in terms of important figures of merit such as pulse energy, pulse duration, peak power and average power. We give some perspectives at the end to emphasize the expected future trends of this technology. © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
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    Non-instantaneous polarization dynamics in dielectric media
    (Berlin : Weierstraß-Institut für Angewandte Analysis und Stochastik, 2014) Hofmann, Michael; Hyyti, Janne; Birkholz, Simon; Bock, Martin; Das, Susanta K.; Grunwald, Rüdiger; Hoffmann, Mathias; Nagy, Tamas; Demircan, Ayhan; Jupé, Marco; Ristau, Detlev; Morgner, Uwe; Brée, Carsten; Woerner, Michael; Elsaesser, Thomas; Steinmeyer, Günter
    Third-order optical nonlinearities play a vital role for generation1,2 and characterization 3-5 of some of the shortest optical pulses to date, for optical switching applications6,7, and for spectroscopy8,9. In many cases, nonlinear optical effects are used far off resonance, and then an instantaneous temporal response is expected. Here, we show for the first time resonant frequency-resolved optical gating measurements1012 that indicate substantial nonlinear polarization relaxation times up to 6.5 fs in dielectric media, i.e., significantly beyond the shortest pulses directly available from commercial lasers. These effects are among the fastest effects observed in ultrafast spectroscopy. Numerical solutions of the time-dependent Schrödinger equation13,14 are in excellent agreement with experimental observations. The simulations indicate that pulse generation and characterization in the ultraviolet may be severely affected by this previously unreported effect. Moreover, our approach opens an avenue for application of frequency-resolved optical gating as a highly selective spectroscopic probe in high-field physics.