Because of their ability to sustain extremely high-amplitude electromagnetic fields and transient density and field profiles,plasma optical components are being developed to amplify,compress,and condition high-power l...Because of their ability to sustain extremely high-amplitude electromagnetic fields and transient density and field profiles,plasma optical components are being developed to amplify,compress,and condition high-power laser pulses.We recently demonstrated the potential to use a relativistic plasma aperture—produced during the interaction of a high-power laser pulse with an ultrathin foil target—to tailor the spatiotemporal properties of the intense fundamental and second-harmonic light generated[Duff et al.,Sci.Rep.10,105(2020)].Herein,we explore numerically the interaction of an intense laser pulse with a preformed aperture target to generate second-harmonic laser light with higher-order spatial modes.The maximum generation efficiency is found for an aperture diameter close to the full width at half maximum of the laser focus and for a micrometer-scale target thickness.The spatial mode generated is shown to depend strongly on the polarization of the drive laser pulse,which enables changing between a linearly polarized TEM01 mode and a circularly polarized Laguerre–Gaussian LG01 mode.This demonstrates the use of a plasma aperture to generate intense higher-frequency light with selectable spatial mode structure.展开更多
Next generation high-power laser facilities are expected to generate hundreds-of-MeV proton beams and operate at multiHz repetition rates, presenting opportunities for medical, industrial and scientific applications r...Next generation high-power laser facilities are expected to generate hundreds-of-MeV proton beams and operate at multiHz repetition rates, presenting opportunities for medical, industrial and scientific applications requiring bright pulses of energetic ions. Characterizing the spectro-spatial profile of these ions at high repetition rates in the harsh radiation environments created by laser–plasma interactions remains challenging but is paramount for further source development.To address this, we present a compact scintillating fiber imaging spectrometer based on the tomographic reconstruction of proton energy deposition in a layered fiber array. Modeling indicates that spatial resolution of approximately 1 mm and energy resolution of less than 10% at proton energies of more than 20 MeV are readily achievable with existing 100 μm diameter fibers. Measurements with a prototype beam-profile monitor using 500 μm fibers demonstrate active readouts with invulnerability to electromagnetic pulses, and less than 100 Gy sensitivity. The performance of the full instrument concept is explored with Monte Carlo simulations, accurately reconstructing a proton beam with a multiple-component spectro-spatial profile.展开更多
基金This work was supported financially by EPSRC(Grant Nos.EP/R006202/1 and EP/V049232/1)and STFC(Grant No.ST/V001612/1)It involved the use of the ARCHIE-WeSt and ARCHER2 high-performance computers,with access to the latter provided via the Plasma Physics HEC Consortia(Grant No.EP/R029148/1)+2 种基金the University of Cambridge Research Computing Service(funded by Grant No.EP/P020259/1)EPOCH was developed under EPSRC Grant No.EP/G054940/1The research has also received funding from Laserlab-Europe(Grant Agreement No.871124,European Union’s Horizon 2020 research and innovation program).
文摘Because of their ability to sustain extremely high-amplitude electromagnetic fields and transient density and field profiles,plasma optical components are being developed to amplify,compress,and condition high-power laser pulses.We recently demonstrated the potential to use a relativistic plasma aperture—produced during the interaction of a high-power laser pulse with an ultrathin foil target—to tailor the spatiotemporal properties of the intense fundamental and second-harmonic light generated[Duff et al.,Sci.Rep.10,105(2020)].Herein,we explore numerically the interaction of an intense laser pulse with a preformed aperture target to generate second-harmonic laser light with higher-order spatial modes.The maximum generation efficiency is found for an aperture diameter close to the full width at half maximum of the laser focus and for a micrometer-scale target thickness.The spatial mode generated is shown to depend strongly on the polarization of the drive laser pulse,which enables changing between a linearly polarized TEM01 mode and a circularly polarized Laguerre–Gaussian LG01 mode.This demonstrates the use of a plasma aperture to generate intense higher-frequency light with selectable spatial mode structure.
基金financially supported by STFC,Dstl and EPSRC(grant numbers EP/R006202/1,EP/V049232/1 and EP/P020607/1)by Laserlab-Europe(grant agreement number 871124,European Union’s Horizon 2020 research and innovation program).
文摘Next generation high-power laser facilities are expected to generate hundreds-of-MeV proton beams and operate at multiHz repetition rates, presenting opportunities for medical, industrial and scientific applications requiring bright pulses of energetic ions. Characterizing the spectro-spatial profile of these ions at high repetition rates in the harsh radiation environments created by laser–plasma interactions remains challenging but is paramount for further source development.To address this, we present a compact scintillating fiber imaging spectrometer based on the tomographic reconstruction of proton energy deposition in a layered fiber array. Modeling indicates that spatial resolution of approximately 1 mm and energy resolution of less than 10% at proton energies of more than 20 MeV are readily achievable with existing 100 μm diameter fibers. Measurements with a prototype beam-profile monitor using 500 μm fibers demonstrate active readouts with invulnerability to electromagnetic pulses, and less than 100 Gy sensitivity. The performance of the full instrument concept is explored with Monte Carlo simulations, accurately reconstructing a proton beam with a multiple-component spectro-spatial profile.
