Vectorial Phase Retrieval for Linear Characterization of Attosecond Pulses (original) (raw)
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Benchmarking accurate spectral phase retrieval of single attosecond pulses
Physical Review A, 2015
A single extreme-ultraviolet (XUV) attosecond pulse or pulse train in the time domain is fully characterized if its spectral amplitude and phase are both determined. The spectral amplitude can be easily obtained from photoionization of simple atoms where accurate photoionization cross sections have been measured from, e.g., synchrotron radiations. To determine the spectral phase, at present the standard method is to carry out XUV photoionization in the presence of a dressing infrared (IR) laser. In this work, we examine the accuracy of current phase retrieval methods (PROOF and iPROOF) where the dressing IR is relatively weak such that photoelectron spectra can be accurately calculated by second-order perturbation theory. We suggest a modified method named swPROOF (scattering wave phase retrieval by omega oscillation filtering) which utilizes accurate one-photon and two-photon dipole transition matrix elements and removes the approximations made in PROOF and iPROOF. We show that the swPROOF method can in general retrieve accurate spectral phase compared to other simpler models that have been suggested. We benchmark the accuracy of these phase retrieval methods through simulating the spectrogram by solving the time-dependent Schrödinger equation numerically using several known single attosecond pulses with a fixed spectral amplitude but different spectral phases.
Attosecond sampling of arbitrary optical waveforms
2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013
Advances in the generation of ultrashort laser pulses, and the emergence of new research areas such as attosecond science, nanoplasmonics, coherent control, and multidimensional spectroscopy, have led to the need for a new class of ultrafast metrology that can measure the electric field of complex optical waveforms spanning the ultraviolet to the infrared. Important examples of such waveforms are those produced by spectral control of ultrabroad bandwidth pulses, or by Fourier synthesis. These are typically tailored for specific purposes, such as to increase the photon energy and flux of high-harmonic radiation, or to control dynamical processes by steering electron dynamics on subcycle time scales. These applications demand a knowledge of the full temporal evolution of the field. Conventional pulse measurement techniques that provide estimates of the relative temporal or spectral phase are unsuited to measure such waveforms. Here we experimentally demonstrate a new, all-optical method for directly measuring the electric field of arbitrary ultrafast optical waveforms. Our method is based on high-harmonic generation (HHG) driven by a field that is the collinear superposition of the waveform to be measured with a stronger probe laser pulse. As the delay between the pulses is varied, we show that the field of the unknown waveform is mapped to energy shifts in the high-harmonic spectrum, allowing a direct, accurate, and rapid retrieval of the electric field with subcycle temporal resolution at the location of the HHG.
Probing attosecond pulse trains using “phase-control” techniques
Physical Review A, 2001
We propose a method for the measurement of attosecond beating structures that result from the superposition of harmonics of laser radiation. It utilizes the phase control of the excitation probability of atoms through different interfering channels. The channels consist of multiphoton excitation by the fundamental frequency and single-photon excitation by the superposition of the harmonic fields, or alternatively, by each harmonic or frequency interval within the bandwidth of each harmonic. The method is sensitive to the relative phase of the harmonics, including phases introduced by chirp, and thus allows evaluation of the temporal structure of the superimposed harmonic fields. An experimental setup for the implementation of the method based on freestanding transmission grating is suggested as well.
Characterizing isolated attosecond pulses with angular streaking
We present a reconstruction algorithm for isolated attosecond pulses, which exploits the phase dependent energy modulation of a photoelectron ionized in the presence of a strong laser field. The energy modulation due to a circularly polarized laser field is manifest strongly in the angle-resolved photoelectron momentum distribution, allowing for complete reconstruction of the temporal and spectral profile of an attosecond burst. We show that this type of reconstruction algorithm is robust against counting noise and suitable for single-shot experiments. This algorithm holds potential for a variety of applications for attosecond pulse sources.
Spatially resolved spectral phase interferometry with an isolated attosecond pulse
Optics Express, 2020
We demonstrate spatially resolved supercontinuum spectral phase interferometry with an isolated attosecond pulse (IAP). The measured spatial-spectral interferogram over the broadband region indicates a high degree of IAP coherence in both spatial and spectral domains. In addition, the spectral-delay interferogram shows periodic temporal oscillations over the full IAP continuous spectrum, which indicates high temporal coherence. The supercontinuum spectral phase interferometry with broadband IAP will contribute to exploring spatiotemporal dispersive electronic dynamics through phase-based spectroscopy in the future.
Ultrashort-pulse characterization from dynamic spectrograms by iterative phase retrieval
Journal of The Optical Society of America B-optical Physics, 1997
We develop a modified version of the dynamic spectrogram that permits complete characterization of an ultrashort optical pulse with fewer approximations than do other schemes. The experimental procedure for such a measurement uses a second-order optical nonlinearity and yet yields an intuitive spectrogram with no inherent symmetry constraints or ambiguity. We describe and demonstrate pulse-shape reconstruction from this type of spectrogram. Phase retrieval is performed by means of an iterative algorithm.
Electronic wavefunctions probed by all-optical attosecond interferometry
Nature Photonics
Photoelectron spectroscopy is a powerful method that provides insight into the quantum mechanical properties of a wide range of systems. The ionized electron wavefunction carries information on the structure of the bound orbital, the ionic potential as well as the photo-ionization dynamics itself. While photoelectron spectroscopy resolves the absolute amplitude of the wavefunction, retrieving the spectral phase information has been a long-standing challenge. Here, we transfer the electron phase retrieval problem into an optical one by measuring the time-reversed process of photoionization-photo-recombination-in attosecond pulse generation. We demonstrate all-optical interferometry of two independent phase-locked attosecond light sources. This measurement enables us to directly determine the phase shift associated with electron scattering in simple quantum systems such as helium and neon, over a large energy range. In addition, the strong-field nature of attosecond pulse generation resolves the dipole phase around the Cooper minimum in argon through a single scattering angle, along with phase signatures of multi-electron effects. Our study bears the prospect of probing complex orbital phases in molecular systems as well as electron correlations through resonances subject to strong laser fields.
Complete temporal reconstruction of attosecond high-harmonic pulse trains
New Journal of Physics, 2010
The method of complete reconstruction of attosecond bursts has been demonstrated for attosecond high-harmonic pulse trains. The retrieved harmonic field provided detailed information about the envelope and the individual attosecond pulses contained in the attosecond pulse train. The time-frequency analysis revealed complicated spectral chirp structures and the contribution of different quantum paths to attosecond pulse formation. Contents 7 4. Time-frequency analysis of attosecond pulse trains 9 5. Conclusion 12 Acknowledgment 12 References 12
Journal of Physics B: Atomic, Molecular and Optical Physics, 2019
Attosecond Pulse Trains (APT) generated by high-harmonic generation (HHG) of high-intensity near-infrared (IR) laser pulses have proven valuable for studying the electronic dynamics of atomic and molecular species. However, the high intensities required for high-photon-energy, high-flux HHG usually limit the class of adequate laser systems to repetition rates below 10 kHz. Here, APT’s generated from the 100 kHz, 160 W, 40 fs laser system (HR-1) currently under commissioning at the extreme light infrastructure attosecond light pulse source (ELI-ALPS) are reconstructed using the reconstruction of attosecond beating by interference of two-photon Transitions (RABBIT) technique. These experiments constitute the first attosecond time-resolved photoelectron spectroscopy measurements with attosecond pulses performed at 100 kHz repetition rate and one of the first experiments performed at ELI-ALPS in the framework of projects commissioning its newly installed technologies. These RABBIT measu...