Partially coherent ultrafast spectrography

Bourassin-Bouchet, C.; Couprie, Marie-Emmanuelle

doi:10.1038/ncomms7465

Cited by 49 publications

(28 citation statements)

References 51 publications

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“…Pure state (i.e., fully coherent) descriptions may for instance severely underestimate the retrieved pulse durations in ultrashortpulse characterization methods using partially coherent beams, as discussed in Ref. 54. Our SQUIRRELS method includes the possibility of mixed states, which are generally closer to experimental scenarios, and is thus more widely applicable.…”

Section: Application Of Rabbittmentioning

confidence: 97%

Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy

et al. 2017

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We introduce a framework for the preparation, coherent manipulation and characterization of free-electron quantum states, experimentally demonstrating attosecond pulse trains for electron microscopy. Specifically, we employ phaselocked single-color and two-color optical fields to coherently control the electron wave function along the beam direction. We establish a new variant of quantum state tomography -"SQUIRRELS" -to reconstruct the density matrices of freeelectron ensembles and their attosecond temporal structure. The ability to tailor and quantitatively map electron quantum states will promote the nanoscale study of electron-matter entanglement and the development of new forms of ultrafast electron microscopy and spectroscopy down to the attosecond regime.Optical, electron and x-ray microscopy and spectroscopy reveal specimen properties via spatial and spectral signatures imprinted onto a beam of radiation or electrons. Leaving behind the traditional paradigm of idealized, simple probe beams, advanced optical techniques increasingly harness tailored probes, or even their quantum properties and probe-sample entanglement. The rise of structured illumination microscopy 1 , pulse shaping 2 , and multidimensional 3 and quantum-optical spectroscopy 4 exemplify this development. Similarly, electron microscopy explores the use of shaped electron beams exhibiting particular spatial symmetries 5 or angular momentum 6,7 , and novel measurement schemes involving quantum aspects of electron probes have been proposed 8,9 . Ultrafast imaging and spectroscopy with electrons and x-rays are the basis for an ongoing revolution in the understanding of dynamical processes in matter on atomic scales [10][11][12][13] . The underlying technology heavily rests on laser science for the 2 generation and characterization of ever-shorter femtosecond electron 10,14 and xray [15][16][17] probe pulses, with examples in optical pulse compression 18 and streaking spectroscopy [19][20][21] . The temporal structuring of electron probe beams is facilitated by time-dependent fields in the radio-frequency [22][23][24] , terahertz 18,25 or optical domains. Promising a further leap in temporal resolution, recent findings suggest that ultrafast electron diffraction and microscopy with optically phasecontrolled and sub-cycle, attosecond-structured wave functions may be feasible 8,[26][27][28][29][30] . Specifically, light-field control may translate the temporal resolution of ultrafast transmission electron microscopy (UTEM) 31,32 and electron diffraction (UED) 10,33 , currently at about 200 fs 34 and 20 fs 14,23 , respectively, to the range of attoseconds 26,27,35 . However, such future technologies call for means to both prepare and fully analyze the corresponding quantum states of free electrons.Here, we demonstrate the coherent control and attosecond density modulation of free-electron quantum states using multiple phase-locked optical interactions. Moreover, we introduce quantum state tomography for free electrons, providing crucial e...

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Section: Application Of Rabbittmentioning

confidence: 97%

Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy

et al. 2017

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“…One area of future work will be directed towards optimizing the integration step in the algorithm for speed, perhaps using techniques that have already been employed in FFT algorithms. Another area of future work will investigate whether the concept of partial coherence can be incorporated into the retrieval process, as has already been done for the PCGPA routine [26]. The inclusion of partial coherence into any realistic retrieval routine seems an absolute necessity given the uncertainty involved with any precision measurement of this kind.…”

Section: Resultsmentioning

confidence: 99%

Volkov transform generalized projection algorithm for attosecond pulse characterization

et al. 2016

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An algorithm for characterizing attosecond extreme ultraviolet pulses that is not bandwidth-limited, requires no interpolation of the experimental data, and makes no approximations beyond the strongfield approximation is introduced. This approach fully incorporates the dipole transition matrix element into the retrieval process. Unlike attosecond retrieval methods such as phase retrieval by omega oscillation filtering (PROOF), or improved PROOF, it simultaneously retrieves both the attosecond and infrared (IR) pulses, without placing fundamental restrictions on the IR pulse duration, intensity or bandwidth. The new algorithm is validated both numerically and experimentally, and is also found to have practical advantages. These include an increased robustness to noise, and relaxed requirements for the size of the experimental dataset and the intensity of the streaking pulse.

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“…That is, there are many more measurements than required for reconstructing the pulse uniquely. This redundancy makes these techniques powerful, giving rise to robustness to noise and misalignment as well as allowing reconstructing a pulse at higher temporal resolution from the temporal scanning steps in FROG [17] and reconstructing multiple pulses from a single FROG trace [18,19]. However, the measured data for each scanning step in FROG or for specific dispersion in d-scan is not redundant; in fact, it does not even contain enough information to reconstruct the pulse.…”

Section: Discussionmentioning

confidence: 99%

Deep learning reconstruction of ultrashort pulses from 2D spatial intensity patterns recorded by an all-in-line system in a single-shot

et al. 2020

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We propose a simple all-in-line single-shot scheme for diagnostics of ultrashort laser pulses, consisting of a multi-mode fiber, a nonlinear crystal and a CCD camera. The system records a 2D spatial intensity pattern, from which the pulse shape (amplitude and phase) are recovered, through a fast Deep Learning algorithm. We explore this scheme in simulations and demonstrate the recovery of ultrashort pulses, robustness to noise in measurements and to inaccuracies in the parameters of the system components. Our technique mitigates the need for commonly used iterative optimization reconstruction methods, which are usually slow and hampered by the presence of noise. These features make our concept system advantageous for real time probing of ultrafast processes and noisy conditions. Moreover, this work exemplifies that using deep learning we can unlock new types of systems for pulse recovery.

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Partially coherent ultrafast spectrography

Cited by 49 publications

References 51 publications

Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy

Attosecond electron pulse trains and quantum state reconstruction in ultrafast transmission electron microscopy

Volkov transform generalized projection algorithm for attosecond pulse characterization

Deep learning reconstruction of ultrashort pulses from 2D spatial intensity patterns recorded by an all-in-line system in a single-shot

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