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Femtosecond all-optical synchronization of an X-ray free-electron laser.

Schulz S, Grguraš I, Behrens C, Bromberger H, Costello JT, Czwalinna MK, Felber M, Hoffmann MC, Ilchen M, Liu HY, Mazza T, Meyer M, Pfeiffer S, Prędki P, Schefer S, Schmidt C, Wegner U, Schlarb H, Cavalieri AL - Nat Commun (2015)

Bottom Line: To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed.Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses.Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.

View Article: PubMed Central - PubMed

Affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.

ABSTRACT
Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.

No MeSH data available.


Related in: MedlinePlus

FLASH FEL facility.A macro-pulse of electron bunches is generated in a normal conducting photoinjector. Superconducting modules accelerate the bunches up to 1.25 GeV. Each bunch is compressed at intermediate energies of 150 and 450 MeV in magnetic chicanes. The arrival times of the electron bunches are measured with respect to the master laser oscillator after each compression stage and final acceleration (measurement stations indicated by orange dots in the schematic). The arrival times are incorporated in the feedback control loops for the amplitude and phase of the accelerating fields. The stabilized relativistic electron bunches are used to generate the SASE FEL pulses. Experiments can be carried out in conjunction with an external optical laser, which is synchronized to the master laser oscillator.
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f1: FLASH FEL facility.A macro-pulse of electron bunches is generated in a normal conducting photoinjector. Superconducting modules accelerate the bunches up to 1.25 GeV. Each bunch is compressed at intermediate energies of 150 and 450 MeV in magnetic chicanes. The arrival times of the electron bunches are measured with respect to the master laser oscillator after each compression stage and final acceleration (measurement stations indicated by orange dots in the schematic). The arrival times are incorporated in the feedback control loops for the amplitude and phase of the accelerating fields. The stabilized relativistic electron bunches are used to generate the SASE FEL pulses. Experiments can be carried out in conjunction with an external optical laser, which is synchronized to the master laser oscillator.

Mentions: The FEL driving electron bunch is initiated with several electronvolts (eV) of kinetic energy at its source and requires hundreds of metres of linear accelerator systems to reach its final relativistic energy at the gigaelectronvolt (GeV) level. Shown schematically in Fig. 1, at FLASH a picosecond laser is used to generate the electron bunch by photoemission from the cathode in the injector. The photoelectrons are immediately extracted and accelerated to mitigate Coulomb repulsion and corresponding beam quality degradation. The energy is then further increased in RF accelerator modules. Once the electron bunch is relativistic, it can be compressed to achieve the final charge density required for SASE X-ray emission in the undulator.


Femtosecond all-optical synchronization of an X-ray free-electron laser.

Schulz S, Grguraš I, Behrens C, Bromberger H, Costello JT, Czwalinna MK, Felber M, Hoffmann MC, Ilchen M, Liu HY, Mazza T, Meyer M, Pfeiffer S, Prędki P, Schefer S, Schmidt C, Wegner U, Schlarb H, Cavalieri AL - Nat Commun (2015)

FLASH FEL facility.A macro-pulse of electron bunches is generated in a normal conducting photoinjector. Superconducting modules accelerate the bunches up to 1.25 GeV. Each bunch is compressed at intermediate energies of 150 and 450 MeV in magnetic chicanes. The arrival times of the electron bunches are measured with respect to the master laser oscillator after each compression stage and final acceleration (measurement stations indicated by orange dots in the schematic). The arrival times are incorporated in the feedback control loops for the amplitude and phase of the accelerating fields. The stabilized relativistic electron bunches are used to generate the SASE FEL pulses. Experiments can be carried out in conjunction with an external optical laser, which is synchronized to the master laser oscillator.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4309427&req=5

f1: FLASH FEL facility.A macro-pulse of electron bunches is generated in a normal conducting photoinjector. Superconducting modules accelerate the bunches up to 1.25 GeV. Each bunch is compressed at intermediate energies of 150 and 450 MeV in magnetic chicanes. The arrival times of the electron bunches are measured with respect to the master laser oscillator after each compression stage and final acceleration (measurement stations indicated by orange dots in the schematic). The arrival times are incorporated in the feedback control loops for the amplitude and phase of the accelerating fields. The stabilized relativistic electron bunches are used to generate the SASE FEL pulses. Experiments can be carried out in conjunction with an external optical laser, which is synchronized to the master laser oscillator.
Mentions: The FEL driving electron bunch is initiated with several electronvolts (eV) of kinetic energy at its source and requires hundreds of metres of linear accelerator systems to reach its final relativistic energy at the gigaelectronvolt (GeV) level. Shown schematically in Fig. 1, at FLASH a picosecond laser is used to generate the electron bunch by photoemission from the cathode in the injector. The photoelectrons are immediately extracted and accelerated to mitigate Coulomb repulsion and corresponding beam quality degradation. The energy is then further increased in RF accelerator modules. Once the electron bunch is relativistic, it can be compressed to achieve the final charge density required for SASE X-ray emission in the undulator.

Bottom Line: To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed.Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses.Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.

View Article: PubMed Central - PubMed

Affiliation: Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.

ABSTRACT
Many advanced applications of X-ray free-electron lasers require pulse durations and time resolutions of only a few femtoseconds. To generate these pulses and to apply them in time-resolved experiments, synchronization techniques that can simultaneously lock all independent components, including all accelerator modules and all external optical lasers, to better than the delivered free-electron laser pulse duration, are needed. Here we achieve all-optical synchronization at the soft X-ray free-electron laser FLASH and demonstrate facility-wide timing to better than 30 fs r.m.s. for 90 fs X-ray photon pulses. Crucially, our analysis indicates that the performance of this optical synchronization is limited primarily by the free-electron laser pulse duration, and should naturally scale to the sub-10 femtosecond level with shorter X-ray pulses.

No MeSH data available.


Related in: MedlinePlus