Extreme-ultraviolet vector-vortex beams from high harmonic generation

[EN]Structured light in the short-wavelength regime opens exciting avenues for the study of ultrafast spin and electronic dynamics. Here, we demonstrate theoretically and experimentally the generation of vector-vortex beams (VVB) in the extreme ultraviolet through high-order harmonic generation (HHG). The up-conversion of VVB, which are spatially tailored in their spin and orbital angular momentum, is ruled by the conservation of the topological Pancharatnam charge in HHG. Despite the complex propagation of the driving beam, high-harmonic VVB are robustly generated with smooth propagation properties. Remarkably, we find out that the conversion efficiency of high-harmonic VVB increases with the driving topological charge. Our work opens the possibility to synthesize attosecond helical structures with spatially varying polarization, a unique tool to probe spatiotemporal dynamics in inhomogeneous media or polarization-dependent systems.European Research Council (851201); Ministerio de Ciencia de Innovación y Universidades, Agencia Estatal de Investigación and European Social Fund (PID2019-106910GB-I00, RYC-2017-22745); Junta de Castilla y León and FEDER Funds (SA287P18); Université Paris-Saclay (2012-0333T-OASIS, 50110000724-OPTX, PhOM REC-2019-074-MAOHAm); Conseil Régional, Île-de-France (501100003990); Barcelona Supercomputing Center (FI-2020-3-0013)

Efficient aberrations pre-compensation and wavefront correction with a deformable mirror in the middle of a petawatt-class CPA laser system

AbstractIn this paper, we describe the experimental validation of the technique of correction of wavefront aberration in the middle of the laser amplifying chain. This technique allows the correction of the aberrations from the first part of the laser system, and the pre-compensation of the aberrations built in the second part. This approach will allow an effective aberration management in the laser chain, to protect the optical surfaces and optimize performances, and is the only possible approach for multi-petawatt laser system from the technical and economical point of view. This approach is now possible after the introduction of new deformable mirrors with lower static aberrations and higher dynamic than the standard devices

Extreme-ultraviolet structured beams via high harmonic generation

Funding European Research Council (851201); Ministerio de Ciencia de Innovación y Universidades, Agencia Estatal de Investigaci ́on and European Social Fund (PID2019106910GB-I00, RYC-2017-22745); Junta de Castilla y León and FEDER Funds (SA287P18); Université ParisSaclay (2012-0333TOASIS, 50110000724-OPTX, PhOM REC-2019-074-MAOHAm); Conseil Régional, I ˆle-de-France (501100003990); Barcelona Supercomputing Center (FI2020-3-0013).Vigorous efforts to harness the topological properties of light have enabled a multitude of novel applications. Translating the applications of structured light to higher spatial and temporal resolutions mandates their controlled generation, manipulation, and thorough characterization in the short-wavelength regime. Here, we resort to high-order harmonic generation (HHG) in a noble gas to upconvert near-infrared (IR) vector, vortex, and vector-vortex driving beams that are tailored, respectively, in their spin angular momentum (SAM), orbital angular momentum (OAM), and simultaneously in their SAM and OAM. We show that HHG enables the controlled generation of extreme-ultraviolet (EUV) vector beams exhibiting various spatially dependent polarization distributions, or EUV vortex beams with a highly twisted phase. Moreover, we demonstrate the generation of EUV vector-vortex beams (VVB) bearing combined characteristics of vector and vortex beams. We rely on EUV wavefront sensing to unambiguously affirm the topological charge scaling of the HHG beams with the harmonic order. Interestingly, our work shows that HHG allows for a synchronous controlled manipulation of SAM and OAM. These EUV structured beams bring in the promising scenario of their applications at nanometric spatial and sub-femtosecond temporal resolutions using a table-top harmonic source

Extreme-ultraviolet structured beams via high harmonic generation

Funding European Research Council (851201); Ministerio de Ciencia de Innovación y Universidades, Agencia Estatal de Investigaci ́on and European Social Fund (PID2019106910GB-I00, RYC-2017-22745); Junta de Castilla y León and FEDER Funds (SA287P18); Université ParisSaclay (2012-0333TOASIS, 50110000724-OPTX, PhOM REC-2019-074-MAOHAm); Conseil Régional, I ˆle-de-France (501100003990); Barcelona Supercomputing Center (FI2020-3-0013).Vigorous efforts to harness the topological properties of light have enabled a multitude of novel applications. Translating the applications of structured light to higher spatial and temporal resolutions mandates their controlled generation, manipulation, and thorough characterization in the short-wavelength regime. Here, we resort to high-order harmonic generation (HHG) in a noble gas to upconvert near-infrared (IR) vector, vortex, and vector-vortex driving beams that are tailored, respectively, in their spin angular momentum (SAM), orbital angular momentum (OAM), and simultaneously in their SAM and OAM. We show that HHG enables the controlled generation of extreme-ultraviolet (EUV) vector beams exhibiting various spatially dependent polarization distributions, or EUV vortex beams with a highly twisted phase. Moreover, we demonstrate the generation of EUV vector-vortex beams (VVB) bearing combined characteristics of vector and vortex beams. We rely on EUV wavefront sensing to unambiguously affirm the topological charge scaling of the HHG beams with the harmonic order. Interestingly, our work shows that HHG allows for a synchronous controlled manipulation of SAM and OAM. These EUV structured beams bring in the promising scenario of their applications at nanometric spatial and sub-femtosecond temporal resolutions using a table-top harmonic source

Caractérisation et contrôle de la répartition d'énergie et du front d'onde d'impulsions femtosecondes

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Design and characterization of a near-diffraction-limited femtosecond 100-TW 10-Hz high-intensity laser system

International audienceWe present the design and characterization of a femtosecond high-intensity laser system emitting a near-diffraction-limited beam. This system was dimensioned in order to reach intensities in excess of 10^20 W/cm^2 at a high repetition rate for ultrahigh-field physics experiments. We describe the improvements that were added to a conventional chirp pulse amplification configuration in order to decrease the deleterious effects of gain narrowing, gain shifting, thermal focusing in the amplifier stages, and spatial degradation due to multipass amplification processes

Refraction of light by light in vacuum

6 pages, 4 figuresInternational audienceIn very intense electromagnetic fields, the vacuum refractive index is expected to be modified due to non linear QED properties. Up to now, these predictions are tested by searching phase shifts in the propagation of polarized light through uniform magnetic fields. We propose a new approach which consists in producing a vacuum index gradient and send a light beam trough it in order to detect its angular deviation. The vacuum index gradient, similar to a "prismatic vacuum", is created by the interaction of two very intense and ultra short laser pulses, used as pump pulses. At the maximum of the index gradient, the deflection angle of the probe pulse is estimated to be $2 \ 10^{-13} \times (\frac{w_0}{10 \mu\mathrm{m}})^{-3} \times \frac{I}{1 \mathrm{J}}$ radians, where $I$ is the total energy of the two pump pulses and $w_0$ is the minimum waist (fwhm) at the interaction area of the two pump pulses. Assuming the most intense laser pulses attainable by the LASERIX facility ($I = 25$ J, 30 fs fwhm duration, 800 nm central wavelength) and assuming a minimum waist of $w=10 \mu\mathrm{m}$ (fwhm) (corresponding to an intensity of the order of $10^{21}$ W/cm$^2$), the expected deflection angle is about $5 \ 10^{-12}$ radians at the maximum of the index gradient. We propose to measure it with a Sagnac interferometer

Experimental Results for Multiphoton Nonlinear Photoemission Processes on Phil Test Line

International audienceOne of the prerequisites for the next generation high luminosity light sources is the availability of the short electron bunches. It also has several applications in other domains, including medical diagnostics and high-resolution imaging. In principle, using photoelectric effect a short electron bunch can initially be generated by illuminating a photocathode with an ultra-short light pulse of appropriate wavelength. Strong EM fields from a RF gun or similar accelerating structures, synchronized with the incoming laser pulses, are then used to accelerate these electron bunches initially up to an energy of tens of MeV. We present our preliminary results on the experimental investigation of two-photon nonlinear photoemission processes for the generation of picosecond, low-charge electron bunches conducted at PHIL photoinjector facility. A comparison of the emission efficiency and bunch characteristics with the single photon emission process is also made

Cohérence temporelle et largeur spectrale des lasers XUV transitoires pompés en incidence rasante

posterInternational audienc