G. Vieux | University of Strathclyde (original) (raw)
Papers by G. Vieux
We report on high efficiency energy transfer in a GeV-class laser wakefield accelerator. Both the... more We report on high efficiency energy transfer in a GeV-class laser wakefield accelerator. Both the transfer of energy from the laser to the plasma wakefield, and from the plasma to the accelerated electron beam were diagnosed experimentally by simultaneous measurement of the deceleration of laser photons and the accelerated electrons as a function of acceleration length. The extraction efficiency, which we define as the ratio of the energy gained by the electron beam to the energy lost by the self-guided laser mode, was maximised at 27±2 pulse compression. At higher densities, the laser was observed to fully redshift over an entire octave, from 800 nm to 1600 nm.
The advent of laser systems based on the chirped pulse amplification (CPA) technique has allowed ... more The advent of laser systems based on the chirped pulse amplification (CPA) technique has allowed the production of femtosecond pulses with intensities up to 1021W/cm2. However reaching these intensities and beyond is proving very expensive and the development of future laser systems may need to use a different technology. Amplifiers based on stimulated Raman backscattering (RBS) in plasma could represent the next generation of amplifiers [1, 2]. Ra-man backscattering is a very promising means of transferring energy from a long pump pulse to a short probe pulse. Moreover, plasma can withstand extremely high power densities and therefore is a very robust gain medium. Raman backscattering in plasma can be simply characterized as the resonant decay of an incident photon into a frequency downshifted scattered photon and an electron plasma wave (a Langmuir wave). The frequency and wave number matching conditions are given by: ω0 = ω1+ωp, k0 = k1+ kp (1) where ω0,1,p and k0,1,p are the fre...
Relativistic Plasma Waves and Particle Beams as Coherent and Incoherent Radiation Sources III, Apr 24, 2019
The laser wake-field accelerator (LWFA) traditionally produces high brightness, quasi-monoenerget... more The laser wake-field accelerator (LWFA) traditionally produces high brightness, quasi-monoenergetic electron beams with Gaussian-like spatial and angular distributions. In the present work we investigate the generation of ultra-relativistic beams with ring-like structures in the blowout regime of the LWFA using a dual stage accelerator. A density down-ramp triggers injection after the first stage and is used to produce ring-like electron spectra in the 300-600 MeV energy range. These well defined, annular beams are observed simultaneously with the on-axis, high energy electron beams, with a divergence of a few milliradians. The rings have quasi-monoenergetic energy spectra with an RMS spread estimated to be less than 5%. Particle-in-cell simulations confirm that off-axis injection provides the electrons with the initial transverse momentum necessary to undertake distinct betatron oscillations within the plasma bubble during their acceleration process.
Scientific Reports
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Plasma Physics and Controlled Fusion
and Ciocarlan, C. and Ersfeld, B. and Hur, M. S. and Lepipas, P. and Manahan, G. G. and Raj, G. a... more and Ciocarlan, C. and Ersfeld, B. and Hur, M. S. and Lepipas, P. and Manahan, G. G. and Raj, G. and Reboredo Gil, D. and Subiel, A. and Welsh, G. H. and Wiggins, S. M. and Yoffe, S. R. and Farmer, J. P. and Aniculaesei, C. and Brunetti, E. and Yang, X. and Heathcote, R. and Nersisyan, G. and Lewis, C. L. S. and Pukhov, A. and Dias, J. M. and Jaroszynski, D. A. (2017) An ultra-high gain and efficient amplifier based on Raman amplification in plasma. Scientific Reports, 7. pp. 1-10. ISSN 2045-2322 , http://dx.doi.org/10.1038/s41598-017-01783-4
1.Introduction Electromagnetically induced transparency (EIT) means that an electromagnetic wave ... more 1.Introduction Electromagnetically induced transparency (EIT) means that an electromagnetic wave is enabled to propagate through an otherwise opaque medium by the interaction with a second wave. In plasma, the coupling mechanism is a modulation of the plasma frequency, which determines the refractive properties of the plasma. This can be due to a relativistic increase of the electron mass, or due to a variation in electron density caused by longitudinal plasma oscillations driven by the ponderomotive force associated with the beat of the waves. The original study of EIT by Harris [1] employs a three-wave model, incorporating two transverse electromagnetic waves – with frequencies p ω ω > 0 , p s ω ω < , where p ω is the
. Howeverreaching these intensities and beyond is proving very expensive and the development of f... more . Howeverreaching these intensities and beyond is proving very expensive and the development of futurelaser systems may need to use a different technology. Amplifiers based on stimulated Ramanbackscattering (RBS) in plasma could represent the next generation of amplifiers [1, 2]. Ra-man backscattering is a very promising means of transferring energy from a long pump pulseto a short probe pulse. Moreover, plasma can withstand extremely high power densities andtherefore is a very robust gain medium.Raman backscattering in plasma can be simply characterized as the resonant decay of anincident photon into a frequency downshifted scattered photon and an electron plasma wave (aLangmuir wave). The frequency and wave number matching conditions are given by:ω
Journal of Physics: Conference Series
Laser wakefield accelerators (LWFAs) are promising sources of high brightness particle and radiat... more Laser wakefield accelerators (LWFAs) are promising sources of high brightness particle and radiation beams with many possible applications, ranging from scientific research to medicine, industry and border security. The Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) is a university-based facility employing the use of two high-power, ultrashort pulse lasers to advance research, development and application of laser-plasma accelerators. Here we report on recent advancements in LWFA research at SCAPA and upcoming research programmes to demonstrate proof-of-concept applications of the LWFA.
We report on high efficiency energy transfer in a GeV-class laser wakefield accelerator. Both the... more We report on high efficiency energy transfer in a GeV-class laser wakefield accelerator. Both the transfer of energy from the laser to the plasma wakefield, and from the plasma to the accelerated electron beam were diagnosed experimentally by simultaneous measurement of the deceleration of laser photons and the accelerated electrons as a function of acceleration length. The extraction efficiency, which we define as the ratio of the energy gained by the electron beam to the energy lost by the self-guided laser mode, was maximised at 27pm227\pm227pm2 % by tuning of the plasma density, plasma length and incident laser pulse compression. At higher densities, the laser was observed to fully redshift over an entire octave, from 800~nm to 1600~nm.
XXII International Symposium on High Power Laser Systems and Applications, Jan 3, 2019
Here we explore ways of transforming laser radiation into incoherent and coherent electromagnetic... more Here we explore ways of transforming laser radiation into incoherent and coherent electromagnetic radiation using laserdriven plasma waves. We present several examples based on the laser wakefield accelerator (LWFA) and show that the electron beam and radiation from the LWFA has several unique characteristics compared with conventional devices. We show that the energy spread can be much smaller than 1% at 130-150 MeV. This makes LWFAs useful tools for scientists undertaking time resolved probing of matter subject to stimuli. They also make excellent imaging tools. We present experimental evidence that ultra-short XUV pulses, as short as 30 fs, are produced directly from an undulator driven by a LWFA, due to the electron bunches having a duration of a few femtoseconds. By extending the electron energy to 1 GeV, and for 1-2 fs duration pulses of 2 nm radiation peak powers of several MW per pC can be produced. The increased charge at higher electron energies will increase the peak power to GW levels, making the LWFA driven synchrotron an extremely useful source with a spectral range extending into the water window. With the reduction in size afforded by using LWFA driven radiation sources, and with the predicted advances in laser stability and repletion rate, ultra-short pulse radiation sources should become more affordable and widely used, which could change the way science is done.
Scientific Reports
Laser-wakefield accelerators (LWFAs) are high acceleration-gradient plasma-based particle acceler... more Laser-wakefield accelerators (LWFAs) are high acceleration-gradient plasma-based particle accelerators capable of producing ultra-relativistic electron beams. Within the strong focusing fields of the wakefield, accelerated electrons undergo betatron oscillations, emitting a bright pulse of X-rays with a micrometer-scale source size that may be used for imaging applications. Non-destructive X-ray phase contrast imaging and tomography of heterogeneous materials can provide insight into their processing, structure, and performance. To demonstrate the imaging capability of X-rays from an LWFA we have examined an irregular eutectic in the aluminum-silicon (Al-Si) system. The lamellar spacing of the Al-Si eutectic microstructure is on the order of a few micrometers, thus requiring high spatial resolution. We present comparisons between the sharpness and spatial resolution in phase contrast images of this eutectic alloy obtained via X-ray phase contrast imaging at the Swiss Light Source (SLS) synchrotron and X-ray projection microscopy via an LWFA source. An upper bound on the resolving power of 2.7 ± 0.3 μm of the LWFA source in this experiment was measured. These results indicate that betatron X-rays from laser wakefield acceleration can provide an alternative to conventional synchrotron sources for high resolution imaging of eutectics and, more broadly, complex microstructures. Laser-wakefield acceleration (LWFA) is a method for producing high-energy electron beams using the accelerating field structure produced in the wake of a high-power, ultrashort pulsed laser propagating through low density plasma. During wakefield acceleration, an electron bunch "surfs" on the electric wave generated by the light pressure of an intense laser pulse 1. This wave induces a strong longitudinal electric field that remains in phase with the relativistic driver, enabling relativistic electrons to gain significant energy from the accelerating field over long distances. Due to the lack of a breakdown limit in a plasma accelerator, accelerating gradients 1000 times stronger than those produced in conventional sources can be produced 1,2 and the generation of high energy electron
Springer Proceedings in Physics, 2007
ABSTRACT Thanks to the most recent works on x-ray laser and on high order harmonics (HHG), it is ... more ABSTRACT Thanks to the most recent works on x-ray laser and on high order harmonics (HHG), it is now possible to produce an energetic beam having at the same time the required optical properties. The solution consists in seeding the XRL amplifier medium with another beam (HHG). This experiment was successfully realized in LOA. We studied seeding of two x-ray laser transitions, 4d-4p at 32.8 nm in Kr8+ and 5d-5p 41.8 nm in Xe8+. The amplifying medium is generated by focussing a high energy circularly polarized, 35 fs 10 Hz Ti: sapphire laser system in a few mm cell filled with gas (xenon or krypton). We succeeded to increase from a factor 10 to 200 the HHG energy, without deteriorating their optical qualities. The resulting beam was polarized, coherent and we estimate the output energy to be about 0.5 εJ.
Proceedings of SPIE - The International Society for Optical Engineering, 2005
We studied seeding of two x-ray laser transitions, 4d-4p at 32.8 nm in Kr8+ and 5d-5p 41.8 nm in ... more We studied seeding of two x-ray laser transitions, 4d-4p at 32.8 nm in Kr8+ and 5d-5p 41.8 nm in Xe8+. The amplifying medium is generated by focussing a high energy circularly polarized, 35 fs 10 Hz Ti: sapphire laser system in a few mm cell filled with gas (xenon or krypton).We succeeded to increase from a factor 10 to 200 the input HHG energy, without deteriorating their optical qualities. The resulting beam was polarized, coherent and we estimate the output energy to be about 1 muJ.
Physical Review A, 2006
We report on experimental and theoretical studies of a collisionally pumped, optical-field-ionize... more We report on experimental and theoretical studies of a collisionally pumped, optical-field-ionized soft-x-ray laser (SXRL) at 41.8nm driven in capillary tubes with smooth inner surface. A detailed experimental study has been conducted in order to understand the key effects related to guiding in this configuration. The amplifying plasma was created inside few-cm-long capillary tubes, and maximum extreme ultraviolet emission was
Laser-driven plasma wakefield accelerators (LWFAs) based on table-top terawatt lasers have the po... more Laser-driven plasma wakefield accelerators (LWFAs) based on table-top terawatt lasers have the potential of producing high brightness ultra-short electron bunches that are ideal for driving free-electron lasers (FELs). These sources are excellent candidates for reaching the x-ray spectral region. However, the creation of a compact radiation source based on this technology requires a number of difficult challenges to be met. Currently, LWFAs produce beams with excellent transverse emittance but very large energy spectra. To meet the requirement that the fractional energy spread should be less than the universal FEL gain parameter, rho, the electron bunch injected into the accelerator must occupy a small region of phase space. We will discuss a new project that has recently been set up in the UK to develop LWFA technology and apply to the creation of a compact FEL. To meet the stringent injection requirements, 10 MeV ultra-shot injection electron bunches, with durations a fraction of ...
Journal de Physique IV (Proceedings), 2006
... Le tube capillaire est monté sur un support motorisé à 5 degrés de liberté (3 translations et... more ... Le tube capillaire est monté sur un support motorisé à 5 degrés de liberté (3 translations et 2 rotations) qui permet le micro-positionnement du plan d'entrée du tube capillaire sur l'axe et dans le plan focal du faisceau laser. Un ...
New Journal of Physics, 2015
2015 40th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2015
Here we explore ways of converting laser radiation into coherent electromagnetic radiation using ... more Here we explore ways of converting laser radiation into coherent electromagnetic radiation using laser-driven plasma waves. Several schemes are presented, including colliding laser pulses in magnetized plasma and utilizing ultra-short electron bunches from laser wakefield accelerators to produce intense single-cycle pulses through coherent transition radiation and fewcycle coherent synchrotron radiation in undulators and plasma channels. These sources rely on high current electron bunches with femtosecond durations, which can result in radiation over a broad range of frequencies from 1 to 10 5 THz.
ABSTRACT The development, understanding and application of laser-driven particle accelerators req... more ABSTRACT The development, understanding and application of laser-driven particle accelerators require accurate measurements of the beam properties, in particular emittance, energy spread and bunch length. Here we report measurements and simulations showing that laser wakefield accelerators can produce beams of quality comparable to conventional linear accelerators.
We report on high efficiency energy transfer in a GeV-class laser wakefield accelerator. Both the... more We report on high efficiency energy transfer in a GeV-class laser wakefield accelerator. Both the transfer of energy from the laser to the plasma wakefield, and from the plasma to the accelerated electron beam were diagnosed experimentally by simultaneous measurement of the deceleration of laser photons and the accelerated electrons as a function of acceleration length. The extraction efficiency, which we define as the ratio of the energy gained by the electron beam to the energy lost by the self-guided laser mode, was maximised at 27±2 pulse compression. At higher densities, the laser was observed to fully redshift over an entire octave, from 800 nm to 1600 nm.
The advent of laser systems based on the chirped pulse amplification (CPA) technique has allowed ... more The advent of laser systems based on the chirped pulse amplification (CPA) technique has allowed the production of femtosecond pulses with intensities up to 1021W/cm2. However reaching these intensities and beyond is proving very expensive and the development of future laser systems may need to use a different technology. Amplifiers based on stimulated Raman backscattering (RBS) in plasma could represent the next generation of amplifiers [1, 2]. Ra-man backscattering is a very promising means of transferring energy from a long pump pulse to a short probe pulse. Moreover, plasma can withstand extremely high power densities and therefore is a very robust gain medium. Raman backscattering in plasma can be simply characterized as the resonant decay of an incident photon into a frequency downshifted scattered photon and an electron plasma wave (a Langmuir wave). The frequency and wave number matching conditions are given by: ω0 = ω1+ωp, k0 = k1+ kp (1) where ω0,1,p and k0,1,p are the fre...
Relativistic Plasma Waves and Particle Beams as Coherent and Incoherent Radiation Sources III, Apr 24, 2019
The laser wake-field accelerator (LWFA) traditionally produces high brightness, quasi-monoenerget... more The laser wake-field accelerator (LWFA) traditionally produces high brightness, quasi-monoenergetic electron beams with Gaussian-like spatial and angular distributions. In the present work we investigate the generation of ultra-relativistic beams with ring-like structures in the blowout regime of the LWFA using a dual stage accelerator. A density down-ramp triggers injection after the first stage and is used to produce ring-like electron spectra in the 300-600 MeV energy range. These well defined, annular beams are observed simultaneously with the on-axis, high energy electron beams, with a divergence of a few milliradians. The rings have quasi-monoenergetic energy spectra with an RMS spread estimated to be less than 5%. Particle-in-cell simulations confirm that off-axis injection provides the electrons with the initial transverse momentum necessary to undertake distinct betatron oscillations within the plasma bubble during their acceleration process.
Scientific Reports
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Plasma Physics and Controlled Fusion
and Ciocarlan, C. and Ersfeld, B. and Hur, M. S. and Lepipas, P. and Manahan, G. G. and Raj, G. a... more and Ciocarlan, C. and Ersfeld, B. and Hur, M. S. and Lepipas, P. and Manahan, G. G. and Raj, G. and Reboredo Gil, D. and Subiel, A. and Welsh, G. H. and Wiggins, S. M. and Yoffe, S. R. and Farmer, J. P. and Aniculaesei, C. and Brunetti, E. and Yang, X. and Heathcote, R. and Nersisyan, G. and Lewis, C. L. S. and Pukhov, A. and Dias, J. M. and Jaroszynski, D. A. (2017) An ultra-high gain and efficient amplifier based on Raman amplification in plasma. Scientific Reports, 7. pp. 1-10. ISSN 2045-2322 , http://dx.doi.org/10.1038/s41598-017-01783-4
1.Introduction Electromagnetically induced transparency (EIT) means that an electromagnetic wave ... more 1.Introduction Electromagnetically induced transparency (EIT) means that an electromagnetic wave is enabled to propagate through an otherwise opaque medium by the interaction with a second wave. In plasma, the coupling mechanism is a modulation of the plasma frequency, which determines the refractive properties of the plasma. This can be due to a relativistic increase of the electron mass, or due to a variation in electron density caused by longitudinal plasma oscillations driven by the ponderomotive force associated with the beat of the waves. The original study of EIT by Harris [1] employs a three-wave model, incorporating two transverse electromagnetic waves – with frequencies p ω ω > 0 , p s ω ω < , where p ω is the
. Howeverreaching these intensities and beyond is proving very expensive and the development of f... more . Howeverreaching these intensities and beyond is proving very expensive and the development of futurelaser systems may need to use a different technology. Amplifiers based on stimulated Ramanbackscattering (RBS) in plasma could represent the next generation of amplifiers [1, 2]. Ra-man backscattering is a very promising means of transferring energy from a long pump pulseto a short probe pulse. Moreover, plasma can withstand extremely high power densities andtherefore is a very robust gain medium.Raman backscattering in plasma can be simply characterized as the resonant decay of anincident photon into a frequency downshifted scattered photon and an electron plasma wave (aLangmuir wave). The frequency and wave number matching conditions are given by:ω
Journal of Physics: Conference Series
Laser wakefield accelerators (LWFAs) are promising sources of high brightness particle and radiat... more Laser wakefield accelerators (LWFAs) are promising sources of high brightness particle and radiation beams with many possible applications, ranging from scientific research to medicine, industry and border security. The Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) is a university-based facility employing the use of two high-power, ultrashort pulse lasers to advance research, development and application of laser-plasma accelerators. Here we report on recent advancements in LWFA research at SCAPA and upcoming research programmes to demonstrate proof-of-concept applications of the LWFA.
We report on high efficiency energy transfer in a GeV-class laser wakefield accelerator. Both the... more We report on high efficiency energy transfer in a GeV-class laser wakefield accelerator. Both the transfer of energy from the laser to the plasma wakefield, and from the plasma to the accelerated electron beam were diagnosed experimentally by simultaneous measurement of the deceleration of laser photons and the accelerated electrons as a function of acceleration length. The extraction efficiency, which we define as the ratio of the energy gained by the electron beam to the energy lost by the self-guided laser mode, was maximised at 27pm227\pm227pm2 % by tuning of the plasma density, plasma length and incident laser pulse compression. At higher densities, the laser was observed to fully redshift over an entire octave, from 800~nm to 1600~nm.
XXII International Symposium on High Power Laser Systems and Applications, Jan 3, 2019
Here we explore ways of transforming laser radiation into incoherent and coherent electromagnetic... more Here we explore ways of transforming laser radiation into incoherent and coherent electromagnetic radiation using laserdriven plasma waves. We present several examples based on the laser wakefield accelerator (LWFA) and show that the electron beam and radiation from the LWFA has several unique characteristics compared with conventional devices. We show that the energy spread can be much smaller than 1% at 130-150 MeV. This makes LWFAs useful tools for scientists undertaking time resolved probing of matter subject to stimuli. They also make excellent imaging tools. We present experimental evidence that ultra-short XUV pulses, as short as 30 fs, are produced directly from an undulator driven by a LWFA, due to the electron bunches having a duration of a few femtoseconds. By extending the electron energy to 1 GeV, and for 1-2 fs duration pulses of 2 nm radiation peak powers of several MW per pC can be produced. The increased charge at higher electron energies will increase the peak power to GW levels, making the LWFA driven synchrotron an extremely useful source with a spectral range extending into the water window. With the reduction in size afforded by using LWFA driven radiation sources, and with the predicted advances in laser stability and repletion rate, ultra-short pulse radiation sources should become more affordable and widely used, which could change the way science is done.
Scientific Reports
Laser-wakefield accelerators (LWFAs) are high acceleration-gradient plasma-based particle acceler... more Laser-wakefield accelerators (LWFAs) are high acceleration-gradient plasma-based particle accelerators capable of producing ultra-relativistic electron beams. Within the strong focusing fields of the wakefield, accelerated electrons undergo betatron oscillations, emitting a bright pulse of X-rays with a micrometer-scale source size that may be used for imaging applications. Non-destructive X-ray phase contrast imaging and tomography of heterogeneous materials can provide insight into their processing, structure, and performance. To demonstrate the imaging capability of X-rays from an LWFA we have examined an irregular eutectic in the aluminum-silicon (Al-Si) system. The lamellar spacing of the Al-Si eutectic microstructure is on the order of a few micrometers, thus requiring high spatial resolution. We present comparisons between the sharpness and spatial resolution in phase contrast images of this eutectic alloy obtained via X-ray phase contrast imaging at the Swiss Light Source (SLS) synchrotron and X-ray projection microscopy via an LWFA source. An upper bound on the resolving power of 2.7 ± 0.3 μm of the LWFA source in this experiment was measured. These results indicate that betatron X-rays from laser wakefield acceleration can provide an alternative to conventional synchrotron sources for high resolution imaging of eutectics and, more broadly, complex microstructures. Laser-wakefield acceleration (LWFA) is a method for producing high-energy electron beams using the accelerating field structure produced in the wake of a high-power, ultrashort pulsed laser propagating through low density plasma. During wakefield acceleration, an electron bunch "surfs" on the electric wave generated by the light pressure of an intense laser pulse 1. This wave induces a strong longitudinal electric field that remains in phase with the relativistic driver, enabling relativistic electrons to gain significant energy from the accelerating field over long distances. Due to the lack of a breakdown limit in a plasma accelerator, accelerating gradients 1000 times stronger than those produced in conventional sources can be produced 1,2 and the generation of high energy electron
Springer Proceedings in Physics, 2007
ABSTRACT Thanks to the most recent works on x-ray laser and on high order harmonics (HHG), it is ... more ABSTRACT Thanks to the most recent works on x-ray laser and on high order harmonics (HHG), it is now possible to produce an energetic beam having at the same time the required optical properties. The solution consists in seeding the XRL amplifier medium with another beam (HHG). This experiment was successfully realized in LOA. We studied seeding of two x-ray laser transitions, 4d-4p at 32.8 nm in Kr8+ and 5d-5p 41.8 nm in Xe8+. The amplifying medium is generated by focussing a high energy circularly polarized, 35 fs 10 Hz Ti: sapphire laser system in a few mm cell filled with gas (xenon or krypton). We succeeded to increase from a factor 10 to 200 the HHG energy, without deteriorating their optical qualities. The resulting beam was polarized, coherent and we estimate the output energy to be about 0.5 εJ.
Proceedings of SPIE - The International Society for Optical Engineering, 2005
We studied seeding of two x-ray laser transitions, 4d-4p at 32.8 nm in Kr8+ and 5d-5p 41.8 nm in ... more We studied seeding of two x-ray laser transitions, 4d-4p at 32.8 nm in Kr8+ and 5d-5p 41.8 nm in Xe8+. The amplifying medium is generated by focussing a high energy circularly polarized, 35 fs 10 Hz Ti: sapphire laser system in a few mm cell filled with gas (xenon or krypton).We succeeded to increase from a factor 10 to 200 the input HHG energy, without deteriorating their optical qualities. The resulting beam was polarized, coherent and we estimate the output energy to be about 1 muJ.
Physical Review A, 2006
We report on experimental and theoretical studies of a collisionally pumped, optical-field-ionize... more We report on experimental and theoretical studies of a collisionally pumped, optical-field-ionized soft-x-ray laser (SXRL) at 41.8nm driven in capillary tubes with smooth inner surface. A detailed experimental study has been conducted in order to understand the key effects related to guiding in this configuration. The amplifying plasma was created inside few-cm-long capillary tubes, and maximum extreme ultraviolet emission was
Laser-driven plasma wakefield accelerators (LWFAs) based on table-top terawatt lasers have the po... more Laser-driven plasma wakefield accelerators (LWFAs) based on table-top terawatt lasers have the potential of producing high brightness ultra-short electron bunches that are ideal for driving free-electron lasers (FELs). These sources are excellent candidates for reaching the x-ray spectral region. However, the creation of a compact radiation source based on this technology requires a number of difficult challenges to be met. Currently, LWFAs produce beams with excellent transverse emittance but very large energy spectra. To meet the requirement that the fractional energy spread should be less than the universal FEL gain parameter, rho, the electron bunch injected into the accelerator must occupy a small region of phase space. We will discuss a new project that has recently been set up in the UK to develop LWFA technology and apply to the creation of a compact FEL. To meet the stringent injection requirements, 10 MeV ultra-shot injection electron bunches, with durations a fraction of ...
Journal de Physique IV (Proceedings), 2006
... Le tube capillaire est monté sur un support motorisé à 5 degrés de liberté (3 translations et... more ... Le tube capillaire est monté sur un support motorisé à 5 degrés de liberté (3 translations et 2 rotations) qui permet le micro-positionnement du plan d'entrée du tube capillaire sur l'axe et dans le plan focal du faisceau laser. Un ...
New Journal of Physics, 2015
2015 40th International Conference on Infrared, Millimeter, and Terahertz waves (IRMMW-THz), 2015
Here we explore ways of converting laser radiation into coherent electromagnetic radiation using ... more Here we explore ways of converting laser radiation into coherent electromagnetic radiation using laser-driven plasma waves. Several schemes are presented, including colliding laser pulses in magnetized plasma and utilizing ultra-short electron bunches from laser wakefield accelerators to produce intense single-cycle pulses through coherent transition radiation and fewcycle coherent synchrotron radiation in undulators and plasma channels. These sources rely on high current electron bunches with femtosecond durations, which can result in radiation over a broad range of frequencies from 1 to 10 5 THz.
ABSTRACT The development, understanding and application of laser-driven particle accelerators req... more ABSTRACT The development, understanding and application of laser-driven particle accelerators require accurate measurements of the beam properties, in particular emittance, energy spread and bunch length. Here we report measurements and simulations showing that laser wakefield accelerators can produce beams of quality comparable to conventional linear accelerators.