Complete reconstruction of ultra-broadband isolated attosecond pulses including partial averaging over the angular distribution

Gaumnitz, Thomas; Jain, Arohi; Wörner, Hans Jakob

doi:10.1364/oe.26.014719

Cited by 19 publications

(13 citation statements)

References 34 publications

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“…With the recent developments, attosecond chronoscopy has become a major area of research within attosecond science since its first application by Cavalieri et al [4]. The advances in ultrashort pulse generation [9] and characterization [10] further opens opportunities to follow the temporal evolution in a more precise manner.…”

Section: Introductionmentioning

confidence: 99%

Photoionization delays in xenon using single-shot referencing in the collinear back-focusing geometry

et al. 2018

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Attosecond photoemission delays for all the valence (5p 3/2 , 5p 1/2 , 5s, 4d 5/2 , 4d 3/2 ) subshells of xenon have been accessed using the interferometric RABBITT technique. The 4d subshell delays in Xe have been accessed for the first time due to the high photon energy used. A novel technique of single-shot referencing in the collinear back-focusing geometry has been introduced. This enables us to distinguish the signal from principal photoelectron peaks due to ionization by extreme ultraviolet radiation (XUV) only and infrared (IR) -induced sideband (SB) contributions, especially in the regions of spectral overlap.

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Section: Introductionmentioning

confidence: 99%

Photoionization delays in xenon using single-shot referencing in the collinear back-focusing geometry

et al. 2018

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“…In this work, we propose a conditional variation generative network (CVGN) to model the distribution of all possible pulses that satisfy a streaking trace corrupted by Poisson noise. We have incorporated a refined streaking model that considers the photoelectron angular distribution 5 and additional phase delay from Coulomb-laser coupling 3 . The results quantitatively demonstrate the uncertainty in the pulse domain, which arises naturally from the experimental noise, and provide an guideline on the required SNR for future streaking experiments.…”

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confidence: 99%

“…PROOF 4 , Volkov transform generalized projection algorithm (VTGPA) 5,8 and genetic algorithms 4,9,10 consider a phase gate that depends on energy and time, obviating the Central Momentum Approximation in FROG-CRAB. Incorporating the angular distribution of photoelectrons 5,6 have led to a more accurate transition dipole moment that matches the streaking process in experiments. These refined streaking…”

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confidence: 99%

Attosecond pulse retrieval from noisy streaking traces with conditional variational generative network

Zhu

White

Chang

et al. 2020

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Accurate characterization of an attosecond pulse from streaking trace is an indispensable step in studying the ultrafast electron dynamics on the attosecond scale. conventional attosecond pulse retrieval methods face two major challenges: the ability to incorporate a complete physics model of the streaking process, and the ability to model the uncertainty of pulse reconstruction in the presence of noise. Here we propose a pulse retrieval method based on conditional variational generative network (cVGn) that can address both demands. instead of learning the inverse mapping from a streaking trace to a pulse profile, the CVGN models the distribution of the pulse profile conditioned on a given streaking trace measurement, and is thus capable of assessing the uncertainty of the retrieved pulses. this capability is highly desirable for low-photon level measurement, which is typical in attosecond streaking experiments in the water window X-ray range. in addition, the proposed scheme incorporates a refined physics model that considers the Coulomb-laser coupling and photoelectron angular distribution in streaking trace generation. cVGn pulse retrievals under various simulated noise levels and experimental measurement have been demonstrated. the results showed high pulse reconstruction consistency for streaking traces when peak signal-to-noise ratio (SNR) exceeds 6, which could serve as a reference for future learning-based attosecond pulse retrieval. The generation of isolated attosecond extreme ultraviolet (XUV)/soft X-ray pulses is a milestone toward investigating the ultrafast electron dynamics on its natural time scale. Accurate temporal and spectral characterization of these XUV pulses is a crucial step in attosecond pump-probe experiments 1. Because the spectrum of the XUV pulses can be measured relatively easily with a spectrometer, knowing its spectral phase will enable a complete reconstruction of the XUV pulse in both time-and frequency-domain. Adapted from an iterative femtosecond pulse retrieval method FROG (Frequency Resolved Optical Gating), Frequency-resolved optical gating for complete reconstruction of attosecond bursts (FROG-CRAB) has been widely used for phase retrieval from attosecond streaking traces 2. Compared to its femtosecond counterpart FROG, attosecond phase retrieval suffers from both experimental and theoretical challenges. The photon flux of attosecond soft X-ray is much lower than that in a typical FROG experiment, giving rise to higher statistic noise in the streaking trace. Currently the effect of noise on the error and uncertainty of retrieved pulse is yet to be understood, and there lacks a guideline on the signal-to-noise ratio (SNR) requirement for accurate pulse retrieval. In addition, phase retrieval of ultra-broadband XUV/X-ray pulses requires a more thorough theoretic description of the photoelectron wave packet during the streaking process, including its energy and angular distribution, as well as its interaction with the laser field, which are either simplified or omitted in exi...

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“…In Fig. 2B, we present our recent generalization of the VTGPA [3] accounting for multiple overlapping photoelectron bands and angle-integrated streaking spectrograms [4,5]. This method allows for the complete temporal reconstruction of both IR and SXR pulses by including the accurate target atom complex photoionization matrix elements (PMEs), as Fourier transformation is avoided in the reconstruction routine and therefore overcomes the limitations caused by the central momentum approximation (CMA).…”

Section: Methodsmentioning

confidence: 99%

Complete characterisation of attosecond SXR pulses generated by MIR laser sources

et al. 2019

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Attosecond streaking with broadband SXR continua leads to contributions from multiple overlapping lines in the photoelectron spectrum. The Volkov-transform generalized projection algorithm (VTGPA) is generalised to include all contributing photoelectron bands (multi-line VTGPA) for the reconstruction of ultra-broadband SXR continua. We further investigate the influence of the collection angle of photoelectron detectors on attosecond streaking spectrograms and show full reconstruction for angle-integrated streaking traces. Also, the effects of the photoionization dipole matrix elements on the reconstruction are demonstrated.

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Complete reconstruction of ultra-broadband isolated attosecond pulses including partial averaging over the angular distribution

Cited by 19 publications

References 34 publications

Photoionization delays in xenon using single-shot referencing in the collinear back-focusing geometry

Photoionization delays in xenon using single-shot referencing in the collinear back-focusing geometry

Attosecond pulse retrieval from noisy streaking traces with conditional variational generative network

Complete characterisation of attosecond SXR pulses generated by MIR laser sources

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