TH11: Ultrafast sources from mid-IR to THz
L. De Mauro (Ohio State University, USA)
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TH11.2: Frequency divide-and-conquer approach to producing few-cycle mid-IR transients and multi-octave combs
K. L. Vodopyanov, Q. Ru, CREOL The College of Optics and Photonics (United States); P. G. Schunemann, BAE Systems, Nashua, NH, USA (United States); S. Vasilyev, IPG Photonics—Southeast Technology Center, Birmingham, AL, USA (United States); S. B. Mirov, Department of Physics, University of Alabama at Birmingham, Birmingham, AL, USA (United States); A. V. Muraviev, CREOL The College of Optics and Photonics (United States)
We present a new technique for extending few-cycle optical pulses and broadband phase-coherent frequency combs to the mid-IR range (2.5–18 micrometers) – based on subharmonic optical parametric oscillation (OPO), a reverse of the second harmonic generation process, where the frequency comb of a pump laser is transposed to half its frequency and simultaneously spectrally augmented, thanks to an enormous parametric gain bandwidth at degeneracy.
TH11.3: Broadband THz radiation with 50 mW average power
J. Buldt, H. Stark, M. Mueller, C. Jauregui, Friedrich-Schiller-University Jena (Germany); J. Limpert, Friedrich- Schiller-University Jena (Germany) and Helmholtz-Institute Jena (Germany) and Fraunhofer Institute for Applied Optics and Precision Engineering (Germany)
Electromagnetic radiation in the THz spectral region is attracting growing interest due to the increasing number of applications in industry, security, biology, medicine and fundamental science. However, a breakthrough in many applications is still hindered by the limitations of available THz sources. This way, THz particle acceleration, the studies of nonlinear effects and material properties, pump-probe experiments, spectroscopy of aqueous samples and many others can significantly profit from novel, highpower sources in the THz gap. The development of THz sources with high average-power, broad bandwidth and high field strength is driven by this demand of the applications. In this paper we present a first step in average-power scaling of broadband, gas-plasmabased THz sources to an unprecedented average power of 50 mW and discuss the scaling of this type of source towards Watt-level average powers.
TH11.4: Broadband intense THz pulses generated with a mid-infrared OPCPA pump source
C. Gollner, TU Wien (Austria); A. Koulouklidis, Science Program, Texas A&M University at Qatar (Qatar) and Institute of Electronic Structure and Laser (IESL) (Greece); M. Shalaby, Swiss Terahertz Research-Zurich (Switzerland) and Key Lab of Terahertz Optoelctronics (China); C. Brodeur, Swiss Terahertz Research-Zurich (Switzerland); V. Fedorov, Science Program, Texas A&M University at Qatar (Qatar) and P. N. Lebedev Physical Institute of the Russian Academy of Sciences (Russian Federation); S. Tzortakis, Science Program, Texas A&M University at Qatar (Qatar) and Institute of Electronic Structure and Laser (IESL) (Greece) and Department of Materials Science and Technology (Greece); V. Shumakova, TU Wien (Austria); A. Baltuška, A. Pugžlys, TU Wien (Austria) and Center for Physical Sciences & Technology (Lithuania)
We report on THz generation driven by a 3.9 μm Optical Parametric Chirped-Pulse Amplifier (OPCPA), via either optical rectification (OR) in organic crystals or in two-color plasma filaments. In both cases, THz generation benefits from the longwavelength of the mid-IR driving pulses, resulting in higher THz pulse energy, higher saturation fluences and larger spectral bandwidth, as compared to conventional VIS and near-IR pump sources. In the case of THz generation by two-color mid-IR plasma filaments, an outstanding optical to THz conversion efficiency of 2.34% could be achieved, which is more than an order of magnitude higher as compared to short-wavelength driving pulses. The exceptionally high conversion efficiency results in THz pulse energies of 0.185 mJ and broad spectral bandwidth of 15 THz. THz generation by OR in organic crystals pumped by 3.9 μm pulses is prominent due to an extraordinary high optical damage threshold and saturation fluences. No damage of the electro-optic crystal was observed for pump fluences exceeding 120 mJ/cm2, which outpaces conventional near-IR pump sources by an order of magnitude. Whereas the conversion efficiency only starts to saturate at pump fluences of > 60 mJ/cm2, THz energy densities of 1.6 mJ/cm2 can be achieved.
TH12: High harmonic and attosecond pulse technology and science
TH12.1: Phase-matched extreme-ultraviolet frequency-comb generation
G. Porat, JILA (United States); C. M. Heyl, JILA (United States) and Department of Physics, Lund University (Sweden); S. B. Schoun, C. Benko, JILA (United States); N. Dorre, University of Vienna, Faculty of Physics, VCQ &, QuNaBioS (Austria); K. L. Corwin, Department of Physics, Kansas State University (United States); J. Ye, JILA (United States)
Extreme ultraviolet (XUV) laser radiation is commonly produced via high-harmonic generation (HHG) in gases. The lasers that drive this process typically operate at low pulse repetition rates (<100 kHz). Under these operating conditions, the plasma generated by each laser pulse clears the generation volume before the next pulse arrives. Therefore, each laser pulse interacts with fresh plasma-free gas, where phase-matching facilitates efficient HHG. However, applications requiring high counting statistics or frequency-comb precision make high repetition rates (>10 MHz) necessary. Unfortunately, at high repetition rates, plasma accumulates in the XUV generation region and prevents phase-matching, resulting in low HHG efficiency. We use high-temperature gas mixtures to increase the gas translational velocity, thus reduce plasma accumulation and facilitate phase-matching. We experimentally achieve phase-matched HHG at a repetition rate of 77 MHz, generating record power of ~2 mW at 97 nm and ~0.9 mW at 67 nm.
TH12.2: Optics-free focusing and spectral filtering of XUV harmonic beams
C. Valentin, K. Veyrinas, CNRS/CELIA (France); D. Descamps, CEA/CELIA (France); F. Burgy, C. Péjot, F. Catoire, CNRS/CELIA (France); E. Constant, CNRS/ILM (France); E. Mével, Université Bordeaux/CELIA (France)
High harmonics generated in gas by few mJ femtosecond laser beam provide a coherent and ultrafast XUV source. By characterizing the intensity profile and wavefront of XUV high-order harmonics generated in a gas jet, we establish the possibility of focusing XUV beams to micrometer spot size and efficient spectral filtering without using any XUV optics.
TH12.3: Efficient ultrafast, high energy sub-2 cycle driver at 150 kHz
F. Guichard, L. Lavenu, M. Natile, Y. Zaouter, Amplitude Systèmes (France); M. Hanna, X. Délen, P. Georges, Laboratoire Charles Fabry (France)
We present a hybrid dual-stage nonlinear compression scheme allowing to compress 330 fs-pulses generated from a high-energy fiber amplifier down to 6.8 fs pulse duration, with an overall transmission of 61%. This high transmission is obtained by using a first compression stage based on a gas-filled multipass cell, and a second stage based on a large-core gas-filled capillary. The source output is fully characterized in terms of spectral, temporal, spatial, and short- and long-term stability properties. The system’s compactness, stability, and high average power makes it ideally suited to drive high photon flux XUV sources through high harmonic generation.
TH12.4: A beamline combining attosecond-XUV and sub-2-fs deep-UV pulses
A. Cartella, University of Hamburg (Germany); V. Wanie, Center for Free-Electron Laser Science (Germany) and Institut National de la Recherche Scientifique (Canada); M. Galli, Center for Free-Electron Laser Science (Germany) and Institute for Photonics and Nanotechnologies CNR-IFN (Italy) and Department of Physics, Politecnico di Milano (Italy); L. Colaizzi, Center for Free-Electron Laser Science (Germany); D. Pereira Lopes, Department of Physics Politecnico di Milano (Italy); E. P. Månsson, A. Trabattoni, K. Saraswathula, Center for Free-Electron Laser Science (Germany); F. Frassetto, L. Poletto, Institute for Photonics and Nanotechnologies CNR-IFN (Italy); F. Légaré, Institut National de la Recherche Scientifique (Canada); S. Stagira, M. Nisoli, Politecnico di Milano Department of Physics (Italy) and Institute for Photonics and Nanotechnologies CNR-IFN (Italy); R. Martinez Vazquez, R. Osellame, Institute for Photonics and Nanotechnologies CNR-IFN (Italy); F. Calegari, University of Hamburg (Germany) and Center for Free-Electron Laser Science (Germany) and Institute for Photonics and Nanotechnologies CNR-IFN (Italy)
Few-cycle deep ultraviolet pulses are generated by frequency up-conversion of 5-fs near infrared pulses in argon using a laser micromachined fused silica gas cell. The spectrum extends from 210 to 340 nm, with a 1.45-fs transform limited pulse duration. The measured pulses (150 nJ energy, 1.9 fs duration) are synchronized with isolated attosecond XUV pulses, enabling new pathways for the attosecond spectroscopy of bio-relevant molecules.
TH12.5: Waveform-dependent relativistic high-order harmonics and field-driven plasma surface dynamics
G. Ma, Peking University Shenzhen Institute and PKU-HKUST Shenzhen-Hong Kong Institution (China) and Center for Free-Electron Laser Science, DESY (Germany); D. Kormin, Max-Planck-Institut für Quantenoptik (Germany) and Ludwig- Maximilian-Universität München (Germany); A. Borot, W. Dallari, B. Bergues, Max-Planck-Institut für Quantenoptik (Germany); M. Aladi, I. B. Foldes, Wigner Research Centre for Physics, Hungarian Academy of Sciences (Hungary); J. He, Peking University Shenzhen Institute and PKU-HKUST Shenzhen-Hong Kong Institution (China); L. Veisz, Max-Planck-Institut für Quantenoptik (Germany) and Department of Physics, Umeå University (Sweden)
Attosecond XUV-pump XUV-probe experiments demand high brightness attosecond light source benefitting from state-of-the-art ultrashort ultraintense laser technology. Current most promising route towards high energy attosecond light source is through relativistic high-order harmonic generation from plasma surfaces. In this paper, we investigate waveform-dependent relativistic high-order harmonic generation from plasma surfaces, and use spectral interferometry to understand its generation process. The unique interpretation has allowed access to unrevealed temporal structure of the generated few-pulse attotrain with evidence supporting a well-isolated attosecond pulse. It also provides a way to measure field-driven plasma surface motion in its generation process.
TH13: Few-cycle pulses, comb generation, and carrier-envelope phase control
TH13.1: Leveraging novel nonlinear devices for gigahertz frequency combs
A. S. Mayer, University of Vienna (Austria); C. R. Phillips, D. Waldburger, L. M. Krüger, A. Klenner, ETH Zurich (Switzerland); A. R. Johnson, Columbia University (United States); K. Luke, Cornell University (United States); X. Ji, Y. Okawachi, M. Lipson, A. L. Gaeta, Columbia University (United States); C. Langrock, M. M. Fejer, Stanford University (United States); U. Keller, ETH Zurich (Switzerland)
This paper summarizes our recent results on frequency combs from compact modelocked solid-state lasers with gigahertz (GHz) pulse repetition rates. In particular, we present novel approaches to leverage nonlinear optical devices for frequency conversion processes that can be achieved at the low pulse energies (i.e. picojoules) inherently provided by these high-repetition rate lasers. We are focusing on three different nonlinear platforms/processes, that each have enabled new milestones for high-repetitionrate frequency combs:(i) supercontinuum generation (SCG) in silicon nitride waveguides to enable the stabilization of GHz-frequency combs centered at 1 μm, (ii) parametric frequency conversion in periodically poled lithium niobate (PPLN) waveguides to extend the wavelength coverage into the mid-infrared, and (iii) an aperiodically poled lithium niobate (APPLN) device that allowed us to push the repetition rate of semiconductor-saturable-absorber-(SESAM)-modelocked solid-state lasers to 10 GHz using a simple straight-cavity configuration.
TH13.2: High-average-power mid-infrared source for spectroscopy and strong-field physics at 100 kHz
N. Forget, N. Thiré, R. Maksimenka, Y. Pertot, O. Albert, Fastlite (France); G. M. Greetham, E. Springate, M. Towrie, Central Laser Facility (United Kingdom)
We present a 100 kHz, high-power, optical parametric chirped-pulse amplifier (OPCPA) with both wavelength tunability from 1.4 μm to 3.9 μm and carrier-envelope phase stability at ~1.75 μm and ~3.1 μm.
TH13.3: Relativistic-intensity waveform-controlled near-single-cycle pulses from a stretched hollow fiber compressor
M. Ouillé, A. Vernier, F. Böhle, M. Bocoum, S. Haessler, J. Faure, R. Lopez-Martens, ENSTA Paristech (France); T. Nagy, Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (Germany); A. Blummenstein, Laser-Laboratorium Göttingen e.V (Germany); P. Simon, Laser-Laboratorium Göttingen e.V. (Germany); D. Gustas, ENSTA Paristech (France)
We present a laser source delivering TW peak power waveform-controlled 1.5-cycle light fields that can be focused down to relativistic intensity at 1 kHz repetition rate. These pulses are generated via post-compression of high-temporal-contrast 25-fs pulses from a Ti:Sapphire double chirped pulse amplifier in a stretched-hollow-fiber compressor scaled for high peak power. The unique capabilities of this source are demonstrated by observing CEP effects in laser wakefield acceleration of relativistic electrons for the first time.
TH13.4: Sub-50 fs fs efficient nonlinear compression of a 100 W amplifier
F. Guichard, A. Chambinaud, J. Pouysegur, M. Cormier, A. Odier, Y. Zaouter, Q. Mocaer, C. Hönninger, E. Mottay, Amplitude Systèmes (France)
We present a high-power70W, sub-50 fs, 400 μJ source at a high repetition rate of 200 kHz. This source is based on the high-efficiency nonlinear compression of an industrial grade 100 W, 450 fs amplifier through a gas-filled multipass cell (MPC) scheme. The system’s compactness, stability, and high average power makes it ideally suited to develop tabletop, high-flux XUV sources.
TH13.5: Sub-optical-cycle shortwave infrared pulses generation in a cascaded degenerate optical parametric amplifier
Y. Lin, Y. Nabekawa, K. Midorikawa, RIKEN (Japan)
Shortwave infrared pulses of 4.86 fs (0.86 optical cycles) centered at 1.7 μm are successfully generated in a BBObased cascaded degenerate optical parametric amplifier, which is pumped by a home-built red femtosecond laser system.
Weeks, Allen (ELI-DC)
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TH14: Generation of ultrashort optical pulses
TH14.1: Nonlinear pulse compression using multi-pass cells
M. Hanna, L. Lavenu, G. Jargot, N. Daher, X. Delen, Lab Charles Fabry (France); F. Guichard, Y. Zaouter, Amplitude Laser Group (France); P. Georges, Lab Charles Fabry (France)
We describe experiments that take advantage of nonlinear propagation of pulses in multi-pass cells, with the aim to perform temporal compression. Propagation in the cell induces a spatial homogenization of the nonlinear phase, while allowing to retain the accumulation of B-integral in the time domain. We will discuss two experiments done (i) with a gas-filled cells in conjunction with a gas-filled capillary, in normal dispersion regime and (ii) with a cell including a solid-state nonlinear medium, in anomalous dispersion regime. Overall, these techniques allow both excellent power efficiency and energy scaling of pulse compression setups.
TH14.2: Sub-10 fs, 45 W, 3 ŒºJ pulses from a Yb:YAG thin-disk oscillator
G. Barbiero, Ludwig-Maximilians-Universität München (Germany) and Max-Planck-Institut für Quantenoptik (Germany); R. N. Ahmad, Ludwig-Maximilians-Universität München (Germany); H. Wang, Ludwig-Maximilians-Universität München (Germany) and Max-Planck-Institut für Quantenoptik (Germany); F. Köttig, Max-Planck-Institut für die Physik des Lichts (Germany); J. Brons, TRUMPF Laser GmbH (Germany); D. Schade, F. Tani, Max-Planck-Institut für die Physik des Lichts (Germany); P. S. Russell, Max-Planck-Institut für die Physik des Lichts (Germany) and Friedrich-Alexander-Universität Erlangen-Nürnberg (Germany); F. Krausz, Ludwig-Maximilians-Universität München (Germany) and Max-Planck-Institut für Quantenoptik (Germany); H. Fattahi, Max- Planck-Institut für Quantenoptik (Germany)
Nonlinear temporal compression of a 265 fs, 100 W, Yb:YAG Kerr-lens mode-locked thin-disk oscillator to generate sub-10 fs, 45 W pulses at 16 MHz repetition rate is presented.
TH14.3: Dispersion tuning of nonlinear dynamics in gas-filled capillary fibres
T. Grigorova, C. Brahms, F. Belli, J. C. Travers, Heriot-Watt University (United Kingdom)
We experimentally investigate the different regimes of optical nonlinear dynamics that can be accessed in hollow capillary fibres by tuning the zero-dispersion wavelength. We pump a 3 m long, 250 μm diameter, argon-filled hollow capillary fibre with 10 fs pulses at 800 nm. By changing the gas pressure, the zero-dispersion wavelength can be tuned from the vacuum ultraviolet to the infrared. For anomalous dispersion at the pump wavelength, typical soliton and soliton-plasma dynamics are observed, such as self-compression, dispersive-wave emission, soliton blue-shifting and ionization-induced pulse splitting. Normal pump dispersion leads to the generation of 3-octave supercontinua and emission of dispersive waves in higher-order modes.
TH14.4: Adiabatic four-wave mixing for ultrafast sources in optical fibers
X. Ding, Cornell University (United States); K. Harrington, University of Bath (United Kingdom); D. Heberle, N. Flemens, W. Chang, Cornell University (United States); T. Birks, University of Bath (United Kingdom); J. Moses, Cornell University (United States)
Ultrabroadband optical pulses that are compressible down to femtosecond duration with controlled phase and amplitude profile attract considerable interest due to their wide range of scientific and industrial applications. Proposed and demonstrated in the past decade, the concept of adiabatic frequency conversion (AFC) using quadratic nonlinear crystals has received attention due to its ability to simultaneously achieve octave-spanning bandwidth, near-100% efficiency, and phase and amplitude control over the generated ultrafast pulse. However, because of the limited choice of materials, requirement of quasi-phasematching, and lack of waveguiding, applications using AFC have a limited range. We recently proposed the concept of adiabatic fourwave mixing (AFWM) in cubic nonlinear media, generalizing AFC to optical fibers and on-chip waveguides. In this paper, we report the first experimental realization of AFWM using a short tapered photonic crystal fiber to convert sub-100-fs pulses from near-IR to mid-IR wavelengths, demonstrating that broadband, highly efficient AFC can be realized with a simple fiber design. Moreover, we show that AFWM can achieve orders of magnitude larger bandwidth than standard phase-matched four-wave mixing, while having high photon conversion efficiency across the entire conversion bandwidth. With a large range of optical fiber platforms available, we expect AFWM will find wide use for both low- and high-energy ultrafast applications.
TH14.5: Generation and single-shot characterization of femtosecond pulses with high temporal contrast
J. Liu, Shanghai Institute of Optics and Fine Mechanics (China)
High temporal contrast are critically important for an ultra-intense laser pulse. Here we proposed femtosecond fourwave mixing processes for the generation of laser pulses with high temporal contrast and for the application of single-shot characterization of the temporal contrast. By using self-diffraction (SD) process, more than 500 uJ first-order SD pulse with a temporal contrast of 1012 was generated, where a temporal contrast improvement of about 107 was achieved in a single stage which verifies the nice pulse cleaning ability of the SD process. We also demonstrate the generation of 100-μJ-level four-wave mixing signals in a thin glass plate. The generated high-energy CFWM signals are innovatively used as clean sampling pulses of a cross-correlator for single-shot temporal contrast measurement. With a simple homemade setup, the cross-correlator was proved a single-shot measurement ability with a dynamic range of 1010, temporal resolution of about 160 fs and temporal window of 50 ps. This is the first demonstration in which both the dynamic range and the temporal resolution of a single-shot temporal contrast measurement are comparable to those of a commercial delay-scanning cross-correlator. Moreover, a new idea for improving the dynamic-range of a single-shot temporal contrast measurement using novel temporal contrast reduction techniques is proposed.
TH14.6: Highly Flexible Pump-Probe Laser for the Soft-X-Ray Free Electron Laser FLASH
S. Alisauskas, N. Schirmel, T. Lang, B. Manschwetus, J. Zheng, T. Hülsenbusch, I. Hartl, U. Große-Wortmann, C. Mohr, F. Peters, A. Swiderski, DESY (Germany)
We report on an OPCPA-based ultrafast pump-probe laser system, which was recently added to the FLASH2 beamline of the superconducting, high repetition-rate XUV and soft X-ray free-electron laser (FEL) FLASH. The laser system is highly flexible in pulse-duration, center-wavelength and repetition-frequency to serve the various demands of pump-probe experiments.