F15: Ultrahigh peak-power laser systems and related technologies
F15.1: 10 petawatt lasers for extreme light applications
C. Simon-Boisson, Thales LAS France SAS (France)
For extreme physics applications, 10 PW (or more) lasers are required. We report here on the performance of the 10 PW beamlines installed at ELI Nuclear Physics site of Magurele and based on amplification in TiSa crystals. The laser system is based laser is based on a double CPA configuration with an hybrid CPA/OPCPA for the front end. The output of first CPA is sent to the next stage which is a XPW filter which allows to increase the temporal contrast of the pulses by 4 orders of magnitude. Then the output beam is sent to an optically-synchronised dual-stage BBO OPCPA whose role is to provide a further improvement of the contrast ratio by an additional 3-4 orders of magnitude. The second CPA incorporates 5 TiSa amplification stages. The spectral amplitude optimization is ensured through the insertion of spectral filters to compensate spectral effects of the amplification. The final 3-pass amplifier is pumped by multiple lasers to allow distribution of pump energy between the different passes of the beam in the Ti:Sa crystal in order to eliminate transverse lasing effects . Finally the beam is sent to the final compressor equipped with meter-size gold-coated compression gratings. At the output of final amplifier we have measured an energy per pulse of 332 J. We have measured on our diagnostics bench a pulse duration of 22.3 fs. Then the projected energy after the compressor (based on 73% measured efficiency) is 242 J which leads to a potential peak power of 10.9 PetaWatt.
F15.2: A possible chance and a potential challenge for 3-fs 100-petawatt lasers
Z. Li, Osaka University (Japan); N. Miyanaga, Institute for Laser Technology (Japan); J. Kawanaka, Osaka University (Japan)
By using wide-angle non-collinear optical parametric chirped amplification (WNOPCPA), a single-optical-cycle 100 petawatt laser is demonstrated in simulation, which provides a possible chance for sub-exawatt lasers. A spatiotemporal coupling distortion (STCD) induced by imperfect compression grating wave-fronts is introduced, which is a potential challenge for peak power/intensity scaling of femtosecond petawatt lasers.
F15.3: Contrast improvement of few-cycle laser pulses using nonlinear ellipse rotation
S. Nadarajan Achary, X. Zhang, P. Fischer, A. A. Muschet, R. Salh, Umea University (Sweden); A. Tajalli, U. Morgner, Institute of Quantum Optics, Leibniz Universität Hannover (Germany); L. Veisz, Umea University (Sweden)
Temporal filtering and spectral broadening are simultaneously achieved, allowing the compression of 20 fs laser pulses down to sub-4 fs duration through the method of nonlinear elliptical polarization rotation in an argon filled hollow-core fiber. The sub-4 fs source provides ~ 35-μJ energy with an internal efficiency >50%, which is more than from the most commonly used pulsecleaning methods. Further, the contrast is improved by 3 orders of magnitude when measured after amplifying the pulses to 16 TW using non-collinear optical parametric chirped pulse amplification with a prospect to even further enhancement.
F15.4: Generation of 0.3-TW few-cycle driver pulses via efficient cascaded Raman frequency down conversion
G. Coccia, P. Carpeggiani, G. Fan, TU Wien (Austria); Z. Tao, Fudan University (China); E. Kaksis, A. Pugzlys, TU Wien (Austria); V. Cardin, F. Légaré, Institut National de la Recherche Scientifique (Canada); B. Schmidt, Few-Cycle Inc (Canada); A. Baltuska, TU Wien (Austria)
Energy efficient wavelength scaling of ultrashort, near IR laser pulses would be highly beneficial for several applications. For example, the generation of few-cycle, CEP stable, long wavelength IR fields via difference frequency generation of two phase-locked pulses at shifted frequencies. Directly driving with red-shifted pulses of those strong field applications where the ponderomotive potential, with its well known λ² dependence, has a key role, such as in high harmonic generation or filamentation. Reaching atomic and molecular resonances in the proximity of the laser fundamental frequency and its harmonics. So far, optical parametric amplification allowed to produce frequency tunable laser sources, but at the price of low conversion efficiency. Stimulated Raman Scattering frequency shifter have been demonstrated, but both their efficiency and the resulting peak power are also limited. In this work, we demonstrate a single-stage, singe-pulse, frequency down conversion of 10mJ, 220 fs pulses at 1030nm via cascaded rotational stimulated Raman scattering in a nitrogen-filled hollow core fiber. The pulses are red-shifted to 1230nm with more than 80% efficiency, and are subsequently compressed by ordinary chirp mirrors to less than 20fs, resulting in a peak power of 0.3 TW.
F16: Novel methods for shaping and measuring ultrashort pulses
F16.1: Frequency domain nonlinear optics: concept and applications
P. Lassonde, INRS-emt (Canada)
We use the concept of frequency domain nonlinear optics (FNO) to address various challenges related to the development of ultrafast laser sources. We find that FNO is a framework opening the door to novel nonlinear interaction schemes involving broadband, ultrashort pulses. Among the principal applications, we have achieved amplification of two-cycle pulses at 1800nm up to 2.5 TW and we have shown pulse shaping of deep-UV pulses at 207 nm.
The fundamental principle of FNO involves an ultrashort pulse undergoing a nonlinear process as its frequency components are projected spatially onto a frequency axis after optical Fourier transformation. This way, the nonlinear process applies independently over discrete frequencies rather than acting on the whole spectrum at once. After nonlinear conversion, the resulting field is recombined linearly to time domain. This overall operation enables for example to synthesize fields inaccessible with conventional time-domain interactions. FNO is achieved optically by using a pair of gratings and mirrors/lenses in a 4f-configuration, like in a pulse shaper apparatus, and by placing nonlinear crystals at the position corresponding to the Fourier plane of this optical arrangement. While the fundamental concept is simple, it offers various design opportunities useful for instance for developing and scaling ultrashort laser sources based on optical parametric amplification, as well as for frequency conversion purposes.
Full Author List:
F16.3: Relativistic harmonics D-scan for on-target temporal characterization of intense optical pulses
V. Leshchenko, Ludwig-Maximilians-Universität München (Germany) and The Ohio State University (United States); A. Kessel, O. Jahn, M. Krueger, A. Münzer, S. Trushin, Ludwig-Maximilians-Universität München (Germany); L. Veisz, Umea University (Sweden); Z. Major, Ludwig-Maximilians-Universität München (Germany) and GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (Germany); S. Karsch, Ludwig-Maximilians-Universität München (Germany)
Accurate knowledge of the on-target pulse intensity is one of key prerequisites for the correct interpretation of highfield experiments due to their high sensitivity to the exact value of the pulse peak intensity caused by the nonlinearity of underlying processes. There are three parameters determining the peak intensity: pulse energy, spatial and temporal energy distribution. While the detection of pulse energy and spatial profile are well established, the unambiguous temporal characterization of intense optical pulses remains a challenge especially at relativistic intensities and a few-cycle pulse duration. We report on the progress in the temporal characterization of intense laser pulses and present the relativistic surface second harmonic generation dispersion scan (RSSHG-D-scan) — a new approach allowing direct on-target temporal characterization of high-energy few-cycle optical pulses at up to relativistic intensities.
F16.4: Characterization of spatiotemporal coupling with multispectral imaging
C. Dorrer, S. Bahk, Laboratory for Laser Energetics (United States)
We have developed diagnostics based on multispectral imaging to characterize spatiotemporal coupling in broadband optical pulses. The wavefront of the source under test is reconstructed from spectrally resolved experimental traces that are simultaneously measured by a multispectral camera. This approach to spatiotemporal metrology has been demonstrated with an apodized imaged Shack–Hartmann wavefront sensor and a checkerboard spatial shearing interferometer. The pulse front tilt and radial group delay introduced by test components are accurately reconstructed from the spatially and spectrally resolved phase. This concept allows for single-shot spatiotemporal metrology, which is important for the characterization of ultrafast and high-energy laser systems.
F16.5: Phase-matching-free pulse retrieval based on transient absorption in solids
A. Leblanc, P. Lassonde, Institut National de la Recherche Scientifique (Canada); S. Petit, J. Delagnes, CELIA (France); E. Haddad, Institut National de la Recherche Scientifique (Canada); G. Ernotte, Joint Attosecond Science Laboratory, NRC of Canada and U of Ottawa, Ottawa, Ontario, Canada (Canada); M. Bionta, V. Gruson, Institut National de la Recherche Scientifique (Canada); B. Schmidt, Institut National de la Recherche Scientifique (Canada) and few-cycle Inc. (Canada); H. Ibrahim, Institut National de la Recherche Scientifique (Canada); E. Cormier, CELIA (France); F. Légaré, Institut National de la Recherche Scientifique (Canada)
We report a novel metrology tool to characterize femtosecond pulses. It is free of phase matching, enabling to measure pulses with ultra-broadband spectra and very low energy at the limit of the spectrometer detection. Transient absorption in solids is used to switch the transmissivity of a thin sample by photoexcitation with a pump pulse. The transmission drop is probed with the pulse to be characterized which is measured with a spectrometer in function of the pump-probe delay. This frequency resolved optical switching dataset can be described mathematically by a ptychographic equation and therefore the temporal profiles (in amplitude and phase) of both the optical switch and the probe pulse can be extracted with a phase retrieval algorithm. The only spectral limitation of this technique is the transmission spectrum of the solid sample. For instance, by using zinc selenide, it has the capability to characterize pulses with a spectrum spanning from 0.5 to 20μm, denoting more than 4 octaves. This approach was demonstrated experimentally by measuring the profiles of pulses centered at 0.8, 1.5, 1.75, 4, and 10μm, among which the ones centered at 0.8 and 10μm are few-cycle. At 0.8, 1.5, and 1.75μm, it was compared to conventional SHG-FROG measurements, as illustrated on Figure 1 with 7.5fs pulses at 0.8μm. Furthermore, the robustness of this technique was shown by measuring identical pulses with different solid samples and with different pump pulse durations.
F16.6: Active f-to-2f interferometer for carrier-envelope phase locking
G. Steinmeyer, R. Liao, Max-Born-Institute (Germany); Y. Song, M. Hu, Tianjin University (China)
Providing optical gain at 1030 nm with an Yb:fiber amplifier, the signal in the infrared arm of the f-to-2f interferometer is boosted prior to second-harmonic generation. This amplification significantly increases the photon numbers in the detected beat note signal, enabling superior signal-to-noise ratios and improving the residual phase noise in carrier-envelope phase locking of a Ti:sapphire laser. An out-of-loop measurement with a second the f-to-2f interferometer indicates a residual phase jitter of 15 mrad, which corresponds to a timing jitter of only 6 attoseconds and constitutes a new record stabilization results. More imporatantly, however, the active the f-to-2f interferometer opens up an avenue towards carrier-envelope phase locking of currently unstabilizable oscillators and comb sources.