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Compression of X-ray Free Electron Laser Pulses to Attosecond Duration.

Sadler JD, Nathvani R, Oleśkiewicz P, Ceurvorst LA, Ratan N, Kasim MF, Trines RM, Bingham R, Norreys PA - Sci Rep (2015)

Bottom Line: State of the art X-ray Free Electron Laser facilities currently provide the brightest X-ray pulses available, typically with mJ energy and several hundred femtosecond duration.Here we present one- and two-dimensional Particle-in-Cell simulations, utilising the process of stimulated Raman amplification, showing that these pulses are compressed to a temporally coherent, sub-femtosecond pulse at 8% efficiency.Furthermore, evidence is presented that significant Landau damping and wave-breaking may be beneficial in distorting the rear of the interaction and further reducing the final pulse duration.

View Article: PubMed Central - PubMed

Affiliation: Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU.

ABSTRACT
State of the art X-ray Free Electron Laser facilities currently provide the brightest X-ray pulses available, typically with mJ energy and several hundred femtosecond duration. Here we present one- and two-dimensional Particle-in-Cell simulations, utilising the process of stimulated Raman amplification, showing that these pulses are compressed to a temporally coherent, sub-femtosecond pulse at 8% efficiency. Pulses of this type may pave the way for routine time resolution of electrons in nm size potentials. Furthermore, evidence is presented that significant Landau damping and wave-breaking may be beneficial in distorting the rear of the interaction and further reducing the final pulse duration.

No MeSH data available.


Related in: MedlinePlus

Electron phase space diagram for a 1D PIC simulation after 15% of the interaction distance.The FWHM of the seed pulse is enclosed by the solid black lines. The initial Maxwellian distribution is excited to a Langmuir wave which subsequently breaks within the extent of the seed pulse.
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f3: Electron phase space diagram for a 1D PIC simulation after 15% of the interaction distance.The FWHM of the seed pulse is enclosed by the solid black lines. The initial Maxwellian distribution is excited to a Langmuir wave which subsequently breaks within the extent of the seed pulse.

Mentions: A further simulation with similar parameters but an initial seed of 10 times the pump intensity was used to verify this. Its electron phase space diagram, shown in Fig. 3, is plotted near the start of the interaction. The short wavelength Langmuir wave is excited right from the front of the seed pulse but only manages around 20 periods of oscillation before it breaks. This places an upper limit on the final duration of the seed of around 10 cycles. In addition, the distribution is skewed towards negative momentum, suggesting heavy Landau damping from the plasma wave travelling at −0.03c. From the position of the seed pulse FWHM, one can see that both of these effects will cease amplification near the back of the seed pulse and help to shorten it, as the front is amplified more than the rear.


Compression of X-ray Free Electron Laser Pulses to Attosecond Duration.

Sadler JD, Nathvani R, Oleśkiewicz P, Ceurvorst LA, Ratan N, Kasim MF, Trines RM, Bingham R, Norreys PA - Sci Rep (2015)

Electron phase space diagram for a 1D PIC simulation after 15% of the interaction distance.The FWHM of the seed pulse is enclosed by the solid black lines. The initial Maxwellian distribution is excited to a Langmuir wave which subsequently breaks within the extent of the seed pulse.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4645159&req=5

f3: Electron phase space diagram for a 1D PIC simulation after 15% of the interaction distance.The FWHM of the seed pulse is enclosed by the solid black lines. The initial Maxwellian distribution is excited to a Langmuir wave which subsequently breaks within the extent of the seed pulse.
Mentions: A further simulation with similar parameters but an initial seed of 10 times the pump intensity was used to verify this. Its electron phase space diagram, shown in Fig. 3, is plotted near the start of the interaction. The short wavelength Langmuir wave is excited right from the front of the seed pulse but only manages around 20 periods of oscillation before it breaks. This places an upper limit on the final duration of the seed of around 10 cycles. In addition, the distribution is skewed towards negative momentum, suggesting heavy Landau damping from the plasma wave travelling at −0.03c. From the position of the seed pulse FWHM, one can see that both of these effects will cease amplification near the back of the seed pulse and help to shorten it, as the front is amplified more than the rear.

Bottom Line: State of the art X-ray Free Electron Laser facilities currently provide the brightest X-ray pulses available, typically with mJ energy and several hundred femtosecond duration.Here we present one- and two-dimensional Particle-in-Cell simulations, utilising the process of stimulated Raman amplification, showing that these pulses are compressed to a temporally coherent, sub-femtosecond pulse at 8% efficiency.Furthermore, evidence is presented that significant Landau damping and wave-breaking may be beneficial in distorting the rear of the interaction and further reducing the final pulse duration.

View Article: PubMed Central - PubMed

Affiliation: Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU.

ABSTRACT
State of the art X-ray Free Electron Laser facilities currently provide the brightest X-ray pulses available, typically with mJ energy and several hundred femtosecond duration. Here we present one- and two-dimensional Particle-in-Cell simulations, utilising the process of stimulated Raman amplification, showing that these pulses are compressed to a temporally coherent, sub-femtosecond pulse at 8% efficiency. Pulses of this type may pave the way for routine time resolution of electrons in nm size potentials. Furthermore, evidence is presented that significant Landau damping and wave-breaking may be beneficial in distorting the rear of the interaction and further reducing the final pulse duration.

No MeSH data available.


Related in: MedlinePlus