A short overview of the theory of acceleration of thin foils driven by the radiation pressure of superintense lasers is presented. A simple criterion for radiation pressure dominance at intensities around 5×1020W...A short overview of the theory of acceleration of thin foils driven by the radiation pressure of superintense lasers is presented. A simple criterion for radiation pressure dominance at intensities around 5×1020W cm-2is given, and the possibility for fast energy gain in the relativistic regime is discussed.展开更多
Laser–plasma interaction(LPI)at intensities 1015–1016 W·cm^-2 is dominated by parametric instabilities which can be responsible for a significant amount of non-collisional absorption and generate large fluxes o...Laser–plasma interaction(LPI)at intensities 1015–1016 W·cm^-2 is dominated by parametric instabilities which can be responsible for a significant amount of non-collisional absorption and generate large fluxes of high-energy nonthermal electrons.Such a regime is of paramount importance for inertial confinement fusion(ICF)and in particular for the shock ignition scheme.In this paper we report on an experiment carried out at the Prague Asterix Laser System(PALS)facility to investigate the extent and time history of stimulated Raman scattering(SRS)and two-plasmon decay(TPD)instabilities,driven by the interaction of an infrared laser pulse at an intensity^1.2×1016 W·cm^-2 with a^100μm scalelength plasma produced from irradiation of a flat plastic target.The laser pulse duration(300 ps)and the high value of plasma temperature(~4 ke V)expected from hydrodynamic simulations make these results interesting for a deeper understanding of LPI in shock ignition conditions.Experimental results show that absolute TPD/SRS,driven at a quarter of the critical density,and convective SRS,driven at lower plasma densities,are well separated in time,with absolute instabilities driven at early times of interaction and convective backward SRS emerging at the laser peak and persisting all over the tail of the pulse.Side-scattering SRS,driven at low plasma densities,is also clearly observed.Experimental results are compared to fully kinetic large-scale,two-dimensional simulations.Particle-in-cell results,beyond reproducing the framework delineated by the experimental measurements,reveal the importance of filamentation instability in ruling the onset of SRS and stimulated Brillouin scattering instabilities and confirm the crucial role of collisionless absorption in the LPI energy balance.展开更多
Dielectric nanocavities are emerging as a versatile and powerful tool for the linear and nonlinear manipulation of light at the nanoscale. In this work, we exploit the effective coupling of electric and toroidal modes...Dielectric nanocavities are emerging as a versatile and powerful tool for the linear and nonlinear manipulation of light at the nanoscale. In this work, we exploit the effective coupling of electric and toroidal modes in Al Ga As nanodimers to locally enhance both electric and magnetic fields while minimizing the optical scattering, thereby optimizing their second-harmonic generation efficiency with respect to the case of a single isolated nanodisk. We also demonstrate that proper near-field coupling can provide further degrees of freedom to control the polarization state and the radiation diagram of the second-harmonic field.展开更多
The efficient interaction of light with quantum emitters is crucial to most applications in nano and quantum photonics,such as sensing or quantum information processing.Effective excitation and photon extraction are p...The efficient interaction of light with quantum emitters is crucial to most applications in nano and quantum photonics,such as sensing or quantum information processing.Effective excitation and photon extraction are particularly important for the weak signals emitted by a single atom or molecule.Recent works have introduced novel collection strategies,which demonstrate that large efficiencies can be achieved by either planar dielectric antennas combined with high numerical aperture objectives or optical nanostructures that beam emission into a narrow angular distribution.However,the first approach requires the use of elaborate collection optics,while the latter is based on accurate positioning of the quantum emitter near complex nanoscale architectures;hence,sophisticated fabrication and experimental capabilities are needed.Here we present a theoretical and experimental demonstration of a planar optical antenna that beams light emitted by a single molecule,which results in increased collection efficiency at small angles without stringent requirements on the emitter position.The proposed device exhibits broadband performance and is spectrally scalable,and it is simple to fabricate and therefore applies to a wide range of quantum emitters.Our design finds immediate application in spectroscopy,quantum optics and sensing.展开更多
基金Support from the Italian Ministry of University and Research via the FIR project ‘SULDIS’
文摘A short overview of the theory of acceleration of thin foils driven by the radiation pressure of superintense lasers is presented. A simple criterion for radiation pressure dominance at intensities around 5×1020W cm-2is given, and the possibility for fast energy gain in the relativistic regime is discussed.
基金financial support from the LASERLAB-EUROPE Access to Research Infrastructure activity within the ECs seventh Framework Programfunding from the Euratom research and training programme 2014–2018 under grant agreement No. 633053+4 种基金partially supported by the project ELITAS (ELI Tools for Advanced Simulation) CZ.02.1.01/0.0/0.0/16 013/0001793HIFI (High Field Initiative, CZ.02.1.01/0.0/0.0/15 003/0000449)ADONIS (Advanced research using high-intensity laser produced photons and particles, CZ.02.1.01/0.0/0.0/16 019/0000789)ELITAS (ELI Tools for Advanced Simulations,CZ.02.1.01/0.0/0.0/16 013/0001793)financial support from the Czech Ministry of Education, Youth and Sports within grants LTT17015, LM2015083, and CZ.02.1.01/0.0/0.0/16 013/0001552 (EF16 013/0001552)
文摘Laser–plasma interaction(LPI)at intensities 1015–1016 W·cm^-2 is dominated by parametric instabilities which can be responsible for a significant amount of non-collisional absorption and generate large fluxes of high-energy nonthermal electrons.Such a regime is of paramount importance for inertial confinement fusion(ICF)and in particular for the shock ignition scheme.In this paper we report on an experiment carried out at the Prague Asterix Laser System(PALS)facility to investigate the extent and time history of stimulated Raman scattering(SRS)and two-plasmon decay(TPD)instabilities,driven by the interaction of an infrared laser pulse at an intensity^1.2×1016 W·cm^-2 with a^100μm scalelength plasma produced from irradiation of a flat plastic target.The laser pulse duration(300 ps)and the high value of plasma temperature(~4 ke V)expected from hydrodynamic simulations make these results interesting for a deeper understanding of LPI in shock ignition conditions.Experimental results show that absolute TPD/SRS,driven at a quarter of the critical density,and convective SRS,driven at lower plasma densities,are well separated in time,with absolute instabilities driven at early times of interaction and convective backward SRS emerging at the laser peak and persisting all over the tail of the pulse.Side-scattering SRS,driven at low plasma densities,is also clearly observed.Experimental results are compared to fully kinetic large-scale,two-dimensional simulations.Particle-in-cell results,beyond reproducing the framework delineated by the experimental measurements,reveal the importance of filamentation instability in ruling the onset of SRS and stimulated Brillouin scattering instabilities and confirm the crucial role of collisionless absorption in the LPI energy balance.
基金Australian Research Council(ARC)Education,Audiovisual and Culture Executive Agency(EACEA)(5659/002-001)SATT IdF-Innov UniversitéSorbonne(Double Culture-PhD program)
文摘Dielectric nanocavities are emerging as a versatile and powerful tool for the linear and nonlinear manipulation of light at the nanoscale. In this work, we exploit the effective coupling of electric and toroidal modes in Al Ga As nanodimers to locally enhance both electric and magnetic fields while minimizing the optical scattering, thereby optimizing their second-harmonic generation efficiency with respect to the case of a single isolated nanodisk. We also demonstrate that proper near-field coupling can provide further degrees of freedom to control the polarization state and the radiation diagram of the second-harmonic field.
基金supported by COST(European Cooperation in Science and Technology).
文摘The efficient interaction of light with quantum emitters is crucial to most applications in nano and quantum photonics,such as sensing or quantum information processing.Effective excitation and photon extraction are particularly important for the weak signals emitted by a single atom or molecule.Recent works have introduced novel collection strategies,which demonstrate that large efficiencies can be achieved by either planar dielectric antennas combined with high numerical aperture objectives or optical nanostructures that beam emission into a narrow angular distribution.However,the first approach requires the use of elaborate collection optics,while the latter is based on accurate positioning of the quantum emitter near complex nanoscale architectures;hence,sophisticated fabrication and experimental capabilities are needed.Here we present a theoretical and experimental demonstration of a planar optical antenna that beams light emitted by a single molecule,which results in increased collection efficiency at small angles without stringent requirements on the emitter position.The proposed device exhibits broadband performance and is spectrally scalable,and it is simple to fabricate and therefore applies to a wide range of quantum emitters.Our design finds immediate application in spectroscopy,quantum optics and sensing.
