Showing papers on "Femtosecond pulse shaping published in 2019"
TL;DR: This approach reveals a great tolerance against noisy conditions, delivering reliable retrievals from traces with signal-to-noise ratios down to 5.5%, enabling video-rate reconstructions of ultrashort pulses from dispersion scan traces employing a deep neural network.
Abstract: The knowledge of the temporal shape of femtosecond pulses is of major interest for all their applications. The reconstruction of the temporal shape of these pulses is an inverse problem for characterization techniques, which benefit from an inherent redundancy in the measurement. Conventionally, time-consuming optimization algorithms are used to solve the inverse problems. Here, we demonstrate the reconstruction of ultrashort pulses from dispersion scan traces employing a deep neural network. The network is trained with a multitude of artificial and noisy dispersion scan traces from randomly shaped pulses. The retrieval takes only 16 ms enabling video-rate reconstructions. This approach reveals a great tolerance against noisy conditions, delivering reliable retrievals from traces with signal-to-noise ratios down to 5.
31 citations
TL;DR: High-index dielectric nanoantennas have recently emerged as promising alternatives to plasmonic nanoantenna for concentrating and manipulating light at the nanoscale as mentioned in this paper.
Abstract: High-index dielectric nanoantennas have recently emerged as promising alternatives to plasmonic nanoantennas for concentrating and manipulating light at the nanoscale. For example, gallium phosphid...
17 citations
TL;DR: Nonlinear spatiotemporal dynamics of femtosecond pulses in a hexagonal seven-core silica fiber pumped by a sub-μJ 370 fs Er:fiber chirped pulse amplification (CPA) system were studied.
Abstract: Nonlinear spatiotemporal dynamics of femtosecond pulses in a hexagonal seven-core silica fiber pumped by a sub-μJ 370 fs Er:fiber chirped pulse amplification (CPA) system were studied. Nonlinear pulse shaping and compression in the central core and pedestal coupling to the outer cores were directly measured by frequency-resolved optical gating. Further compression of the pulses spectrally broadened in the multicore fiber down to 53 fs was demonstrated. Two orders of magnitude contrast enhancement of the pulses after compression was observed.
17 citations
TL;DR: It is demonstrated that a one-dimensional (1D) SLM pixel array is sufficient to control both the spectral amplitude and the phase of the amplified pulses.
Abstract: We experimentally demonstrate a novel use of a spatial light modulator (SLM) for shaping ultrashort pulses in time-gated amplification systems. We show that spectral aberrations because of the device's pixelated nature can be avoided by introducing a group delay offset to the pulse via the SLM, followed by a time-gated amplification. Because of phase wrapping, a large delay offset yields a nearly-periodic grating-like phase function (or a phase grating). We show that, in this regime, the phase grating periocidity defines the group delay spectrum applied to the pulse, while the grating's amplitude defines the fraction of light that is delayed. We therefore demonstrate that a one-dimensional (1D) SLM pixel array is sufficient to control both the spectral amplitude and the phase of the amplified pulses.
14 citations
TL;DR: The design of an extreme ultraviolet (XUV) pulse shaper relying on reflective optics will allow tailoring of the time-frequency spectrum of femtosecond pulses generated by seeded free-electron lasers (FEL) and high-harmonic generation (HHG) sources down to a central wavelength of ~15 nm.
Abstract: We present the design of an extreme ultraviolet (XUV) pulse shaper relying on reflective optics. The instrument will allow tailoring of the time-frequency spectrum of femtosecond pulses generated by seeded free-electron lasers (FEL) and high-harmonic generation (HHG) sources down to a central wavelength of ~15 nm. The device is based on the geometry of a 4f grating compressor that is a standard concept in ultrafast laser science and technology. We apply it to shorter wavelengths using grazing-incidence optics operated under ultra-high vacuum conditions. The design blaze angle and the line density of the gratings allow the manipulation of all different harmonics typical for seeded FEL and HHG photon sources without the need of realignment of the instrument and even simultaneously in multi-color experiments. A proof-of-principle pulse shaping experiment using 266 nm laser light has been performed, demonstrating relative phase-control of femtosecond UV pulses.
8 citations
15 Apr 2019
TL;DR: In this paper, a femtosecond laser pulse shaping using an acousto-optic modulator (AOM) in the Fourier plane was shown experimentally, and an effective way of pulse selection and a calibration routine (Fourier shift theorem) was demonstrated.
Abstract: We have shown experimentally the successful engineering of femtosecond pulse shaping at a 76 MHz repetition rate input pulse with an acousto-optic modulator (AOM). High repetition rate (HRR) femtosecond laser pulse shaping using an AOM in the Fourier plane was incomprehensible because of its intrinsic 100 kHz acoustic update limit. We demonstrate an effective way of pulse selection and a calibration routine (Fourier shift theorem), which enables generation of ∼10 MHz shaped output pulses from the HRR input pulse train. We have generated a temporally shifted rectangular shaped pulse profile by applying modulation on both the phase and amplitude of the ‘sinc’ RF modulation function.
6 citations
TL;DR: It is demonstrated that the method considerably improves the amplitude shaping fidelity of phase and amplitude pulse shapers without compromising the phase shaping properties.
Abstract: Broadband femtosecond laser pulses manipulated by pulse shapers based on a liquid crystal spatial light modulator (LC-SLM) inevitably experience periodic spectral distortions due to Fabry-Perot interference effects within the LC-SLM. We present a method, applicable to phase and amplitude pulse shapers based on dual LC-SLMs, that enables the calibration and suppression of the undesired spectral intensity modulations in a non-iterative fashion. We demonstrate that the method considerably improves the amplitude shaping fidelity of phase and amplitude pulse shapers without compromising the phase shaping properties.
5 citations
TL;DR: In this article, an adaptive femtosecond pulse shaping method based on a genetic algorithm was used to manipulate the green and red luminescence tuning in an Er3+-doped glass ceramic under 800-nm femtocond laser field excitation for the first time.
Abstract: Tuning the color output of rare-earth ion doped luminescent nanomaterials has important scientific significance for further extending applications in color displays, laser sources, optoelectronic devices, and biolabeling. In previous studies, pre-designed phase modulation of the femtosecond laser field has been proven to be effective in tuning the luminescence of doped rare-earth ions. Owing to the complex light–matter interaction in the actual experiment, the dynamic range and optimal efficiency for color tuning cannot be determined with the pre-designed phase modulation. This article shares the development of an adaptive femtosecond pulse shaping method based on a genetic algorithm, and its use to manipulate the green and red luminescence tuning in an Er3+-doped glass ceramic under 800-nm femtosecond laser field excitation for the first time. Experimental results show that the intensity ratio of the green and red UC luminescence of the doped Er3+ ions can be either increased or decreased conveniently by the phase-shaped femtosecond laser field with an optimal feedback control. The physical control mechanisms for the color tuning are also explained in detail. This article demonstrates the potential applications of the adaptive femtosecond pulse shaping technique in controlling the color output of doped rare-earth ions.
4 citations
TL;DR: DisCoBALL is presented, which provides tunable group-delay dispersion (GDD) that is high speed, has a large tuning range, and uses off-the-shelf components that are crucial for experiments with ultrashort pulses.
Abstract: We present dispersion compensation by a liquid lens (DisCoBALL), which provides tunable group-delay dispersion (GDD) that is high speed, has a large tuning range, and uses off-the-shelf components. GDD compensation is crucial for experiments with ultrashort pulses. With an electrically tunable lens (ETL) at the Fourier plane of a 4f grating pair pulse shaper, the ETL applies a parabolic phase shift in space and therefore a parabolic phase shift to the laser spectrum, i.e., GDD. The GDD can be tuned with a range greater than 2×105 fs2 at a rate of 100 Hz while maintaining stable coupling into a single-mode fiber.
4 citations
01 May 2019
TL;DR: In this article, the authors demonstrated nonlinear pulse compression at $1.55\ \mu \mathrm{m}$ from 80 fs to 28 fs by using multiple plate continuum generation and femtosecond pulse shaping.
Abstract: We experimentally demonstrated nonlinear pulse compression at $1.55\ \mu \mathrm{m}$ from 80 fs to 28 fs by using multiple plate continuum generation and femtosecond pulse shaping.
2 citations
05 May 2019
TL;DR: In this paper, the authors demonstrated nonlinear pulse compression at 1.55 μm from 80 fs to 28 fs by using multiple plate continuum generation and femtosecond pulse shaping.
Abstract: We experimentally demonstrated nonlinear pulse compression at 1.55 μm from 80 fs to 28 fs by using multiple plate continuum generation and femtosecond pulse shaping.
04 Apr 2019
TL;DR: In this article, a quantum control of ultrafast coherent bond making and subsequent molecular dynamics is experimentally demonstrated by controlling branching ratio into different target molecular states, which is a significant step toward realizing a new quantum coherent photochemistry.
Abstract: Quantum control of ultrafast coherent bond making and subsequent molecular dynamics is experimentally demonstrated by controlling branching ratio into different target molecular states. This is a significant step toward realizing a new quantum coherent photochemistry.
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TL;DR: In this paper, a randomized multiple independent comb shaping (RandoMICS) algorithm for phase-only ultrashort laser pulse replication is proposed, which is realized by random permutations of a regular aperiodic comb.
Abstract: We present a new Randomized Multiple Independent Comb Shaping (RandoMICS) algorithm for phase-only ultrashort laser pulse replication. The benefit of this method is satellite-free generation of programmable pulse sequences. The result is achieved by applying a stochastic comb of disjoint segments of optical frequency continuum with numerically optimized segment width distribution. The algorithm is realized by random permutations of a regular aperiodic comb. Experimental demonstration is performed with an acousto-optic pulse shaper providing broadband transmission function with arbitrarily variable widths of the segments. Suppression of undesired satellite pulses by the factor of 8 is demonstrated as well as generating pulse replicas with doubled usable delay range compared to pulse shaping with periodic transmission combs.
05 May 2019
TL;DR: In this article, optical nonlinear effects in a thin nematic liquid-crystal result from light absorption by the ITO coating of an infrared femtosecond laser, and subsequent spatial shaping characterises the thermal gradient, up to the isotropic phase transition.
Abstract: Optically-induced thermal nonlinear effects in a thin nematic liquid-crystal result from light absorption by the ITO coating of an infrared femtosecond laser. Subsequent spatial shaping characterises the thermal gradient, up to the isotropic phase transition.
TL;DR: An ultrafast spectrum programmable femtosecond laser may enhance the performance of a wide variety of scientific applications, e.g., multi-photon imaging as discussed by the authors, and a digital micromi...
Abstract: An ultrafast spectrum programmable femtosecond laser may enhance the performance of a wide variety of scientific applications, e.g., multi-photon imaging. In this paper, we report a digital micromi...
05 May 2019
TL;DR: In this paper, the authors demonstrate reconfigurable dispersion control of ultrafast laser pulses through a set of silicon metasurfaces forming a Taylor series expansion in optical phase.
Abstract: Metasurfaces offer the ability to control optical dispersion with extreme resolution. Here, we demonstrate reconfigurable dispersion control of ultrafast laser pulses through a set of silicon metasurfaces forming a Taylor series expansion in optical phase. © 2019 The Author(s)
23 Jun 2019
TL;DR: In this article, a femtosecond pulse shaping using a centimetre-scale silicon metasurface acting as both amplitude and phase modulation mask is presented. But it does not address the problem of time-domain modulation.
Abstract: Fourier-transform pulse shaping is the most widely adopted technique for optical pulse shaping, in which shaping is achieved via parallel modulation of spatially separated frequencies without requiring an ultrafast modulator [1]. Recently, dielectric metasurfaces have emerged as a powerful technology for arbitrary control over the amplitude, phase, or polarization of light in a single, compact optical element [2,3]. Here, we offer the first experimental demonstration of femtosecond pulse shaping using a centimetre-scale silicon metasurface acting as both amplitude and phase modulation mask simultaneously. Expanding metasurfaces into the realm of time-domain manipulation will amplify the already significant impact of their application as two-dimensional wavefront shapers, and open new vistas in the field of ultrafast science and technology.
15 Sep 2019
TL;DR: In this paper, the authors demonstrate temporal polarization pulse shaping within a single femtosecond pulse by controlling the spectral phase using dielectric metasurfaces, and demonstrate the ability to control optical dispersion with large bandwidth and high resolution.
Abstract: Metasurfaces offer the ability to control optical dispersion with large bandwidth and high resolution. Here, we demonstrate temporal polarization pulse shaping within a single femtosecond pulse by controlling the spectral phase using dielectric metasurfaces.