The Experts below are selected from a list of 46650 Experts worldwide ranked by ideXlab platform
C. B. Schroeder - One of the best experts on this subject based on the ideXlab platform.
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flexible x ray source with tunable polarization and orbital angular momentum from hermite gaussian Laser Modes driven plasma channel wakefield
Physical review accelerators and beams, 2019Co-Authors: C. B. Schroeder, Jingwei Wang, M Zepf, Bifeng Lei, T Teter, Yu V Kharin, S G RykovanovAbstract:A plasma channel undulator/wiggler may be created through the plasma wakefield excited by the beating of several Hermite-Gaussian Laser Modes propagating in a parabolic plasma channel. Control over both the betatron and undulator forces is conveniently achieved by tuning the amplitude ratios, colors, and order numbers of the Modes. A special structure of the undulator/wiggler field without the focusing force near the propagation axis is generated inside the plasma wakefield by matching the strengths of the fundamental and first-order Hermite-Gaussian Modes. The electron beam only experiences forced undulator oscillations in such a field, which significantly improves the quality of the emitted radiation. Since the value of the undulator strength parameter could be in a wide range, less or larger than unity, it is capable of generating narrow bandwidth x-ray, as well as the synchrotronlike high-energy $\mathrm{x}/\ensuremath{\gamma}$-ray, radiation by harmonics. Additionally, controlling the relative phases between the Laser Modes allows for polarization control of the plasma undulator. High-order harmonics produced from a circularly polarized plasma undulator clearly show the vortex nature and carry well-defined orbital angular momentum.
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transverse wakefield control via phase matched Laser Modes in plasma channels
2018 IEEE Advanced Accelerator Concepts Workshop (AAC), 2018Co-Authors: Blagoje Djordjevic, E. Esarey, C. B. Schroeder, C Benedetti, Wim LeemansAbstract:The superposition of higher-order Laser Modes can be used to control the Laser-driven transverse wakefields in a Laser-plasma accelerator operating in the quasi-linear regime. To avoid slippage and beating, Modes must have equal group velocities. This can be accomplished by geometric tuning, selecting the appropriate mode indices, or frequency tuning, selecting mode frequencies to compensate for the slower propagation of higher-order Modes. This study is relevant for Laser-plasma acceleration experiments demanding greater control over the transverse focusing forces and electron bunch properties.
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Filtering higher-order Laser Modes using leaky plasma channels
Physics of Plasmas, 2018Co-Authors: Blagoje Djordjevic, C. B. Schroeder, Carlo Benedetti, Eric Esarey, Wim LeemansAbstract:Plasma structures based on leaky channels are proposed to filter higher-order Laser mode content. The evolution and propagation of non-Gaussian Laser pulses in leaky channels are studied, and it is shown that, for appropriate Laser-plasma parameters, the higher-order Laser mode content of the pulse may be removed while the fundamental mode remains well-guided. The behavior of multi-mode Laser pulses is described analytically and numerically using envelope equations, including the derivation of the leakage coefficients, and compared to particle-in-cell simulations. Laser pulse propagation, with reduced higher-order mode content, improves guiding in parabolic plasma channels, enabling extended interaction lengths for Laser-plasma accelerator applications.
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plasma channel undulator excited by high order Laser Modes
Scientific Reports, 2017Co-Authors: C. B. Schroeder, Jingwei Wang, M Zepf, S G RykovanovAbstract:The possibility of utilizing plasma undulators and plasma accelerators to produce compact ultraviolet and X-ray sources, has attracted considerable interest for a few decades. This interest has been driven by the great potential to decrease the threshold for accessing such sources, which are mainly provided by a few dedicated large-scale synchrotron or free-electron Laser (FEL) facilities. However, the broad radiation bandwidth of such plasma devices limits the source brightness and makes it difficult for the FEL instability to develop. Here, using multi-dimensional particle-in-cell (PIC) simulations, we demonstrate that a plasma undulator generated by the beating of a mixture of high-order Laser Modes propagating inside a plasma channel, leads to a few percent radiation bandwidth. The strength of the undulator can reach unity, the period can be less than a millimeter, and the number of undulator periods can be significantly increased by a phase locking technique based on the longitudinal tapering. Polarization control of such an undulator can be achieved by appropriately choosing the phase of the Modes. According to our results, in the fully beam loaded regime, the electron current in the plasma undulator can reach 0.3 kA level, making such an undulator a potential candidate towards a table-top FEL.
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Control of focusing fields for positron acceleration in nonlinear plasma wakes using multiple Laser Modes
Physics of Plasmas, 2014Co-Authors: C. B. Schroeder, Carlo Benedetti, Min Chen, Suming Weng, Zheng-ming Sheng, Eric EsareyAbstract:Control of transverse wakefields in the nonlinear Laser-driven bubble regime using a combination of Hermite-Gaussian Laser Modes is proposed. By controlling the relative intensity ratio of the two Laser Modes, the focusing force can be controlled, enabling matched beam propagation for emittance preservation. A ring bubble can be generated with a large longitudinal accelerating field and a transverse focusing field suitable for positron beam focusing and acceleration.
Alexey Belyanin - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear optical interactions of Laser Modes in quantum cascade Lasers
Journal of Modern Optics, 2011Co-Authors: Aleksander K. Wójcik, Federico Capasso, Alexey BelyaninAbstract:We overview the results of recent experimental and theoretical studies of nonlinear dynamics of mid-infrared quantum cascade Lasers (QCLs) associated with nonlinear interactions of Laser Modes. Particular attention is paid to phase-sensitive nonlinear mode mixing which turns out to be quite prominent in QCLs of different kinds and which gives rise to frequency and phase locking of Laser Modes. Nonlinear phase coupling of Laser Modes in QCLs leads to a variety of ultrafast and coherent phenomena: synchronization of transverse Modes, beam steering, the RNGH multimode instability, and generation of mode-locked ultrashort pulses.
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self synchronization of Laser Modes and multistability in quantum cascade Lasers
Physical Review Letters, 2011Co-Authors: Aleksander K. Wójcik, Federico Capasso, Nanfang Yu, Laurent Diehl, Alexey BelyaninAbstract:: We predict and confirm experimentally the regime of complete synchronization between lateral Modes in a quantum cascade Laser, when frequency combs belonging to different lateral Modes merge into a single comb. The synchronization occurs through the transition from multistability to a single stable state and is accompanied by phase locking and beam steering effects.
M Zepf - One of the best experts on this subject based on the ideXlab platform.
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flexible x ray source with tunable polarization and orbital angular momentum from hermite gaussian Laser Modes driven plasma channel wakefield
Physical review accelerators and beams, 2019Co-Authors: C. B. Schroeder, Jingwei Wang, M Zepf, Bifeng Lei, T Teter, Yu V Kharin, S G RykovanovAbstract:A plasma channel undulator/wiggler may be created through the plasma wakefield excited by the beating of several Hermite-Gaussian Laser Modes propagating in a parabolic plasma channel. Control over both the betatron and undulator forces is conveniently achieved by tuning the amplitude ratios, colors, and order numbers of the Modes. A special structure of the undulator/wiggler field without the focusing force near the propagation axis is generated inside the plasma wakefield by matching the strengths of the fundamental and first-order Hermite-Gaussian Modes. The electron beam only experiences forced undulator oscillations in such a field, which significantly improves the quality of the emitted radiation. Since the value of the undulator strength parameter could be in a wide range, less or larger than unity, it is capable of generating narrow bandwidth x-ray, as well as the synchrotronlike high-energy $\mathrm{x}/\ensuremath{\gamma}$-ray, radiation by harmonics. Additionally, controlling the relative phases between the Laser Modes allows for polarization control of the plasma undulator. High-order harmonics produced from a circularly polarized plasma undulator clearly show the vortex nature and carry well-defined orbital angular momentum.
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plasma channel undulator excited by high order Laser Modes
Scientific Reports, 2017Co-Authors: C. B. Schroeder, Jingwei Wang, M Zepf, S G RykovanovAbstract:The possibility of utilizing plasma undulators and plasma accelerators to produce compact ultraviolet and X-ray sources, has attracted considerable interest for a few decades. This interest has been driven by the great potential to decrease the threshold for accessing such sources, which are mainly provided by a few dedicated large-scale synchrotron or free-electron Laser (FEL) facilities. However, the broad radiation bandwidth of such plasma devices limits the source brightness and makes it difficult for the FEL instability to develop. Here, using multi-dimensional particle-in-cell (PIC) simulations, we demonstrate that a plasma undulator generated by the beating of a mixture of high-order Laser Modes propagating inside a plasma channel, leads to a few percent radiation bandwidth. The strength of the undulator can reach unity, the period can be less than a millimeter, and the number of undulator periods can be significantly increased by a phase locking technique based on the longitudinal tapering. Polarization control of such an undulator can be achieved by appropriately choosing the phase of the Modes. According to our results, in the fully beam loaded regime, the electron current in the plasma undulator can reach 0.3 kA level, making such an undulator a potential candidate towards a table-top FEL.
Wim Leemans - One of the best experts on this subject based on the ideXlab platform.
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transverse wakefield control via phase matched Laser Modes in plasma channels
2018 IEEE Advanced Accelerator Concepts Workshop (AAC), 2018Co-Authors: Blagoje Djordjevic, E. Esarey, C. B. Schroeder, C Benedetti, Wim LeemansAbstract:The superposition of higher-order Laser Modes can be used to control the Laser-driven transverse wakefields in a Laser-plasma accelerator operating in the quasi-linear regime. To avoid slippage and beating, Modes must have equal group velocities. This can be accomplished by geometric tuning, selecting the appropriate mode indices, or frequency tuning, selecting mode frequencies to compensate for the slower propagation of higher-order Modes. This study is relevant for Laser-plasma acceleration experiments demanding greater control over the transverse focusing forces and electron bunch properties.
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Filtering higher-order Laser Modes using leaky plasma channels
Physics of Plasmas, 2018Co-Authors: Blagoje Djordjevic, C. B. Schroeder, Carlo Benedetti, Eric Esarey, Wim LeemansAbstract:Plasma structures based on leaky channels are proposed to filter higher-order Laser mode content. The evolution and propagation of non-Gaussian Laser pulses in leaky channels are studied, and it is shown that, for appropriate Laser-plasma parameters, the higher-order Laser mode content of the pulse may be removed while the fundamental mode remains well-guided. The behavior of multi-mode Laser pulses is described analytically and numerically using envelope equations, including the derivation of the leakage coefficients, and compared to particle-in-cell simulations. Laser pulse propagation, with reduced higher-order mode content, improves guiding in parabolic plasma channels, enabling extended interaction lengths for Laser-plasma accelerator applications.
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Laser‐Plasma Wakefield Acceleration with Higher Order Laser Modes
2010Co-Authors: C.g.r. Geddes, E. Cormier-michel, E. Esarey, C. B. Schroeder, Paul Mullowney, Kevin Paul, John R. Cary, Wim LeemansAbstract:Laser-plasma collider designs point to staging of multiple accelerator stages at the 10 GeV level, which are to be developed on the upcoming BELLA Laser, while Thomson Gamma source designs use GeV stages, both requiring efficiency and low emittance. Design and scaling of stages operating in the quasi-linear regime to address these needs are presented using simulations in the VORPAL framework. In addition to allowing symmetric acceleration of electrons and positrons, which is important for colliders, this regime has the property that the plasma wakefield is proportional to the transverse gradient of the Laser intensity profile. We demonstrate use of higher order Laser Modes to tailor the Laser pulse and hence the transverse focusing forces in the plasma. In particular, we show that by using higher order Laser Modes, we can reduce the focusing fields and hence increase the matched electron beam radius, which is important to increased charge and efficiency, while keeping the low bunch emittance required for applications.
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Efficient Electron Injection into Plasma Waves using Higher‐Order Laser Modes
AIP Conference Proceedings, 2006Co-Authors: Pierre Michel, E. Esarey, C. B. Schroeder, Bradley A. Shadwick, Wim LeemansAbstract:Using higher‐order transverse Laser Modes for plasma wakefield excitation, and, in particular, shaping a ring beam with maximum intensity off‐axis, results in shifting the focusing and defocusing phase regions of a plasma wakefield accelerator. This results in a decreased trapping threshold required for electron injection and an increase of the maximum electron energy. This scheme could also be of interest as a method for generating ring electron beams.
Kai-feng Huang - One of the best experts on this subject based on the ideXlab platform.
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High-power structured Laser Modes: direct generation of a vortex array.
Optics letters, 2020Co-Authors: Yung-fu Chen, Y. C. Tseng, M. X. Hsieh, J. C. Tung, Ying Hui Hsieh, H. C. Liang, Kai-feng HuangAbstract:The frequency degeneracy induced by the astigmatism in a nearly hemispherical cavity is originally exploited to generate vortex array Laser Modes with the output power up to 300 mW. The inhomogeneous Helmholtz equation is employed to derive the wave function for manifesting the characteristics of the lasing Modes. The theoretical wave function explicitly reveals the role of the Gouy phase in the formation of vortex arrays. Numerical analyses are further performed to confirm that the thermal lensing effect in the Laser crystal assists the lasing transverse order to increase with increasing pump power. It is believed that the high efficiency enables the present Laser Modes to be useful in the applications of structured vortex beams.
