Hybrid dc–ac electron gun for fs-electron pulse generation

Veisz, László; Kurkin, G.Ya.; Chernov, K. N.; Tarnetsky, V. V.; Apolonski, Alexander; Krausz, Ferenc; Fill, Ernst E.

doi:10.1088/1367-2630/9/12/451

Cited by 65 publications

(90 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For a sufficiently strong RF field strength E 0 , our analysis indicates that it is always possible to produce a short compressed pulse at the specimen a distance L = 10-100cm after the RF cavity -a result that is in agreement with prior analyses [14][15][16]. In other words, electron pulse broadening due to both longitudinal space-charge effects and the initial energy spread upon photoemission can be compensated for by the insertion of an RF cavity.…”

Section: Photoelectron Gun Re-designsupporting

confidence: 88%

Enhanced Functionality for Materials Analysis in the DTEM

Browning¹

2008

View full text Add to dashboard Cite

Section: Photoelectron Gun Re-designsupporting

confidence: 88%

Enhanced Functionality for Materials Analysis in the DTEM

Browning¹

2008

View full text Add to dashboard Cite

“…Second, we consider the inhomogeneous penetration of electric fields into the anode's aperture, which forms a negative lens. The effective focal length of 4L acc is approximately independent of the aperture size (15). Fig.…”

Section: Resultsmentioning

confidence: 86%

“…The interplay of laser parameters and surface morphology defines the initial phase space of photoemission. Second, the provided data and relations shall be useful for energy-filtered diffraction and microscopy (43,44), femtosecond needle sources (45,46), propagation of elliptical packets (47), and for electron pulse compression with time-dependent fields (2,14,15,17). The outlined measurement approach is a practical way to investigate and optimize the energetic, temporal, and spatial characteristics of femtosecond electron packets for these and other applications.…”

Section: Discussionmentioning

confidence: 99%

“…Recently reported studies include such of reaction pathways during phase transformations (2), chemical reactions (3), laser ablation (4), molecular alignment (5), changes at interfaces (6), heating and melting processes (7)(8)(9), cantilever motion (10), or evanescent fields around nanostructures (11), among many others (12). Possibilities to access the attosecond regime of charge density motion are also discussed (13), taking into account the generation of pulses (14)(15)(16) and the quantum dynamics of the scattering process (17).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Single-electron pulses for ultrafast diffraction

Aidelsburger

Kirchner

Krausz

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

154

161

View full text Add to dashboard Cite

Visualization of atomic-scale structural motion by ultrafast electron diffraction and microscopy requires electron packets of shortest duration and highest coherence. We report on the generation and application of single-electron pulses for this purpose. Photoelectric emission from metal surfaces is studied with tunable ultraviolet pulses in the femtosecond regime. The bandwidth, efficiency, coherence, and electron pulse duration are investigated in dependence on excitation wavelength, intensity, and laser bandwidth. At photon energies close to the cathode's work function, the electron pulse duration shortens significantly and approaches a threshold that is determined by interplay of the optical pulse width and the acceleration field. An optimized choice of laser wavelength and bandwidth results in sub-100-fs electron pulses. We demonstrate single-electron diffraction from polycrystalline diamond films and reveal the favorable influences of matched photon energies on the coherence volume of single-electron wave packets. We discuss the consequences of our findings for the physics of the photoelectric effect and for applications of singleelectron pulses in ultrafast 4D imaging of structural dynamics.I nvestigation of structural dynamics in condensed matter and molecules by four-dimensional imaging calls for resolution of Angstrom-scale distances with femtosecond timing. These resolutions are provided by ultrafast electron diffraction and microscopy techniques, which are based on pump-probe arrangements with a femtosecond laser for excitation and with ultrashort electron packets for measuring sequences of atomic-scale structures during changes (1). Recently reported studies include such of reaction pathways during phase transformations (2), chemical reactions (3), laser ablation (4), molecular alignment (5), changes at interfaces (6), heating and melting processes (7-9), cantilever motion (10), or evanescent fields around nanostructures (11), among many others (12). Possibilities to access the attosecond regime of charge density motion are also discussed (13), taking into account the generation of pulses (14-16) and the quantum dynamics of the scattering process (17).These (and many more) achievements are made possible by the use of ultrashort electron packets at multi-kiloelectron-volt energies for time-resolved diffraction and imaging. Such packets can be generated by photoelectric emission from metal films illuminated with femtosecond lasers, followed by acceleration in static or radio-frequency electric fields. In multielectron packets, space-charge effects dominate the temporal structure and energy distribution; hence electron density has to be traded off against resolution (18,19). In contrast, space charge is absent in packets containing only one single electron at a time (12). In this regime, the longitudinal and transverse emittance, and hence the pulse duration, bandwidth, and coherence, are determined by the spatiotemporal statistics of the photoelectric effect.Some theoretical models consider the femtos...

show abstract

“…27 Single-electron pulses have no space charge and can in principle be compressed to attosecond duration using the time-dependent longitudinal fields of a microwave. 28 Alternatively, dense electron packets can be compressed to femtosecond duration. 21,29,30 The singleelectron source, 16 the microwave compressor, 17 an isochronic magnetic lens system, 31 tilted excitation pulses 32 and a coherent diffraction methodology 33 are mostly ready; just the quality of synchronization is not at the desired fewfemtosecond level yet.…”

mentioning

confidence: 99%

Passive optical enhancement of laser-microwave synchronization

Gliserin

Walbran

Baum

2013

Applied Physics Letters

View full text Add to dashboard Cite

Thermal noise is a fundamental limitation for synchronizing microwaves to high-power lasers of low repetition rate. Here, we describe an optical enhancement scheme that concentrates the output power of a fast photodiode into a narrow range of harmonics around a microwave frequency. The scheme is entirely passive and requires no feedback or lock. Using a 5-MHz laser and a microwave at 6.2 GHz, we demonstrate an enhancement of optical-to-microwave conversion by a factor of 4000. The uncorrelated noise on time scales up to 8 min amounts to less than 4 fs, with laser pulses intense enough for pump-probe experiments of structural dynamics.

show abstract

Hybrid dc–ac electron gun for fs-electron pulse generation

Cited by 65 publications

References 24 publications

Enhanced Functionality for Materials Analysis in the DTEM

Enhanced Functionality for Materials Analysis in the DTEM

Single-electron pulses for ultrafast diffraction

Passive optical enhancement of laser-microwave synchronization

Contact Info

Product

Resources

About