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In ultra-intense chirped pulse amplification laser systems, pulses of ultrashort duration and high energy are generated using large spectral bandwidths and large beam diameters. Hence, the spatiotemporal couplings of the laser field can become significant and affect the field structure. The propagation of such pulses is simulated in this work using a code developed in-house, based on Gabor’s decomposition of the initial complex field into Fourier transform limited Gaussian pulse beam terms. Subsequently, the analysis of the temporal, spatial, and angular chirp, as well as pulse front tilt couplings for a super-Gaussian beam of 25 fs duration allows quantification of their signatures in the near field and focus.

We report on the generation and delivery of 10.2 PW peak power laser pulses, using the High Power Laser System at the Extreme Laser Infrastructure – Nuclear Physics facility. In this work we demonstrate for the first time, to the best of our knowledge, the compression and propagation of full energy, full aperture, laser pulses that reach a power level of more than 10 PW.

Optical vortices, generated by a spiral phase plate, were propagated over long distances and focused in the PW experimental area. A deformable mirror was used to correct the low-order distortions, obtaining a doughnut focus.

Shock waves are generated when a laser pulse ablates a thin jet of water. The shocks have irregular initial shapes, but they flatten and generate secondary shocks as they propagate inside the jet. The shocks can then travel together over long distances and be transmitted inside the jet nozzle.

We have shown, for the first time in the world, the production of 10 PW peak power laser pulses and their propagation to an experimental area at the Extreme Light Infrastructure - Nuclear Physics (ELI-NP). We are also steadily running the laser system for experimental campaigns, increasing the output power levels delivered for experiments and fine-tuning the parameters of the laser pulses, the operational procedures, and the operational teams. During our presentation, we will show the laser developments at ELI-NP emphasizing the 10 PW peak power demonstrations and the latest results for the HPLS beam delivery.

We report the generation of unprecedented 10 PetaWatt laser pulses obtained from each of the two beamlines of the High Power Laser System (HPLS) of ELI-NP (Extreme Light Infrastructure – Nuclear Physics) research infrastructure. The laser system is a hybrid system made of a double CPA based on amplification within Titanium Sapphire crystals combined with an OPCPA with a parametric amplification stage boosting the energy to 10 mJ at the entrance of the second CPA. A XPW filter is also inserted between the two CPA and in combination with the OPCPA improves the temporal contrast of the pulses by typically 7 orders of magnitude. The spectral effects occurring during amplification such as gain narrowing and wavelength shifting are compensated through the use of spectral filters. Final amplification stages are involving large aperture Ti:Sapphire crystals (up to 200 mm) which are pumped by high energy frequencydoubled Nd:Glass lasers delivering each 100 J of green light. Laser beams have been amplified respectively up to 332 J and to 342 J of pulse energy at 1 shot per minute without any occurrence of ASE and transverse lasing thanks to index matching fluid surrounding the crystal over is entire length and pump deposition management over the time before each beam pass within the Ti:Sapphire crystal. We have demonstrated full aperture compression by metric gratings of these amplified pulses down to 22.6 fs and therefore made the full demonstration for the first time ever of 10 PW capability from a laser system.

Following the completion of the installation and testing of the HPLS 2x10PW laser system at ELI-NP, prospective experiments related to spectral broadening in thin films for post-compression were performed at the HPLS 100TW output.

We report on a two-arm hybrid high-power laser system (HPLS) able to deliver 2 × 10 PW femtosecond pulses, developed at the Bucharest-Magurele Extreme Light Infrastructure Nuclear Physics (ELI-NP) Facility. A hybrid front-end (FE) based on a Ti:sapphire chirped pulse amplifier and a picosecond optical parametric chirped pulse amplifier based on beta barium borate (BBO) crystals, with a cross-polarized wave (XPW) filter in between, has been developed. It delivers 10 mJ laser pulses, at 10 Hz repetition rate, with more than 70 nm spectral bandwidth and high-intensity contrast, in the range of 1013:1. The high-energy Ti:sapphire amplifier stages of both arms were seeded from this common FE. The final high-energy amplifier, equipped with a 200 mm diameter Ti:sapphire crystal, has been pumped by six 100 J nanosecond frequency doubled Nd:glass lasers, at 1 pulse/min repetition rate. More than 300 J output pulse energy has been obtained by pumping with only 80% of the whole 600 J available pump energy. The compressor has a transmission efficiency of 74% and an output pulse duration of 22.7 fs was measured, thus demonstrating that the dual-arm HPLS has the capacity to generate 10 PW peak power femtosecond pulses. The reported results represent the cornerstone of the ELI-NP 2 × 10 PW femtosecond laser facility, devoted to fundamental and applied nuclear physics research.

The demonstration of the first 10 PW pulses during March 2019 the High Power Laser System at ELI-NP together with extensive tests, provides now the possibility to evaluate the ultrahigh irradiance in reach.

A three-dimensional non-adiabatic model in combination with a rate equation model is used to characterize high-intensity (>10 16 W/cm 2 ) femtosecond laser pulse propagation in atomic gas medium. In these conditions the atoms in the target gas will become multiply charged ions, while the laser pulse will propagate in a medium with high electron concentration created by itself. We obtain pulse characteristics in time, frequency and space domain for two representative cases: 800 nm and 267 nm (third harmonic) multi-cycle pulses which are both of practical importance. We show that the spatial-temporal variation of the refractive index in the macroscopic medium is the primary reason for pulse temporal/spectral and spatial shaping during propagation.

Recently, femtosecond pulse shortening techniques applicable for high peak power (>1 PW) lasers have been an object of intense research [1]. It is motivated by pushing the frontiers of the peak power. Another reason is increasing the temporal resolution in pump-probe experiments. The temporal contrast of these lasers is extremely high (>107) and preserving it after the pulse shortening is still a challenge. The common approach for femtosecond pulse shortening includes spectral broadening in a third order nonlinear medium and residual chirp compensation in a pulse compressor. An alternative approach is based on cascaded second order nonlinearities. Although both methods have been successfully demonstrated [2,3], there is no comparison of their capabilities to preserve the temporal contrast. In this report, we compare these two techniques: considering two criteria: the output pulse duration and the temporal contrast.

A real-time closed feedback loop adaptive optics (AO) set-up has been developed for optical wave front qualification at Extreme Light Infrastructure — Nuclear Physics facility that hosts a dual arm 10 PW high power laser system [1]. The AO allows a dynamic wave front correction associated to optical components for high-peak ultra-short femtosecond laser systems. The AO set-up consists in (1) a Shack-Hartman wave front sensor (SHWFS), for measuring optical wave front deviations, (2) a deformable mirror (DM) that changes its shape in order to modify a distorted optical wave front, (3) a real-time closed control software to calculate the corresponding shape that the DM must assume in order to compensate the wave front distortions, and (4) a second SHWFS that provides wave front measuring capabilities for ∼ 10 mm and 50 mm, respectively, laser beam diameter [2].

Experiments with high power laser systems (HPLS) such as [1] require a completely characterized focal spot: spatially and temporally. In order to study the laser field distribution on the target, we have developed a method to determine the beam shape after propagating in free-space or after the focusing optics. Our numerical simulations proved to be in good agreement with other propagation approaches, and require reasonable computing resources.

Two glass prisms are brought in close proximity. The evanescent field fromthe total internal reflection in one prism is used to obtain a beam with an irradiance tunableover 110 dB, with potential applications from medicine to materials processing.

We report first 10 PW light from the ELI-NP laser. We have obtained at 1 shot/min pulses with 332 J energy before compression and 22.3 fs duration leading to a peak power of 10.9 PW.

International audience; The European Strategy Forum on Research Infrastructures (ESFRI) has selected in 2006 a proposal based on ultra-intense laser fields with intensities reaching up to 1022–1023 W cm−2 called 'ELI' for Extreme Light Infrastructure. The construction of a large-scale laser-centred, distributed pan-European research infrastructure, involving beyond the state-of-the-art ultra-short and ultra-intense laser technologies, received the approval for funding in 2011–2012. The three pillars of the ELI facility are being built in Czech Republic, Hungary and Romania. The Romanian pillar is ELI-Nuclear Physics (ELI-NP). The new facility is intended to serve a broad national, European and International science community. Its mission covers scientific research at the frontier of knowledge involving two domains. The first one is laser-driven experiments related to nuclear physics, strong-field quantum electrodynamics and associated vacuum effects. The second is based on a Compton backscattering high-brilliance and intense low-energy gamma beam (

Extreme Light Infrastructure–Nuclear Physics (ELI–NP) is aiming to use extreme electromagnetic fields for nuclear physics research. The facility, currently under construction at Magurele–Bucharest, will comprise a high power laser system and a very brilliant gamma beam system. The technology involved in the construction of both systems is at the limits of the present-day’s technological capabilities. The high power laser system will consist of two 10 PW lasers and it will produce intensities of up to 10 23 –10 24 W/cm 2 . The gamma beam, produced via Compton backscattering of a laser beam on a relativistic electron beam, will be characterized by a narrow bandwidth (

Hollow Core Inhibited Coupling Fiber (HC-ICF) is preferable for multipetawatt laser-induced plasma diagnostics because of its broadband, low loss and weak chromatic dispersion. The transmission windows of HC-ICF depend on the thickness of the dielectric cladding. In this paper, various designs of HC-ICF are investigated in terms of confinement loss, dielectric overlap, and dispersion parameter.

Silicon substrates were irradiated at normal incidence with a femtosecond Ti:sapphire laser (Quatronix, 90 fs pulse duration, 1 kHz repetition rate, M 2 ~ 1.2, maximum energy peak 350 mJ ) operating at a wavelength of 400 nm and focused via a microscope objective (Newport; UV Objective Model, 37x 0.11 N.A.). The laser scanning was assisted by liquids precursors media such as methanol and 1,1,2-trichlorotrifluoroethane. By altering the processing parameters, such as incident laser energy, scanning speed, and different irradiation media, various surface structures were produced on areas with 1 mm 2 dimensions. We analyzed the dependence of the surface morphology on laser pulse energy, scanning speed and irradiation media. Well ordered areas are developed without imposing any boundary conditions for the capillary waves that coarsens the ripple pattern. To assess biomaterial-driven cell adhesion response we investigated actin filaments organization and cell morphological changes following growth onto processed silicon substrates. Our study of bone cell progenitor interaction with laser nanoprocessed silicon lines has shown that cells anchor mainly to contact points along the nanostructured surface. Consequently, actin filaments are stretched towards the 15 µ m wide parallel lines increasing lateral cell spreading and changing the bipolar shape of mesenchymal stem cells.

It is shown that in the focus of ultra-short pulses of duration t, the equivalent relation s = ct, where c is the speed of light and s the spatial extent of the pulse of the collimated pulse, does not hold. While the duration of one pulse is constant and independent of the measurement point, the spatial extension of the ultra-short pulse can be spatially shorter a factor more than 10 compared to the one obtained from the usual relation. The result is explained in correspondence with the extension of the Rayleigh range. Few femtosecond long gamma bursts can thus be generated in Thomson backscattering experiments performed in the lambda cube regime.

International audience; We present a nickel-like Molybdenum x-ray laser (XRL) based on the transient collisional excitation scheme. Extending the double grazing-incidence pumping scheme to a triple pulse scheme with a nanosecond pre-pulse and two consecutive 3 ps pulses the output power of the XRL can be similar to 6 times increased compared to existing configurations, while using a relatively low total pump energy of 0.7 J. Additionally we show that this setup can be extended to a double stage, oscillator and amplifier stage, XRL.

Based on the lack of consistent literature publications that analyse the effects of laser marking for traceability on various materials, the present paper proposes a study of the influence of such radiation processing on an aluminum alloy, a vastly used material base within several industry fields. For the novelty impact, femtolaser marking has been carried out, besides the standard commercial nanosecond engraving. All the marks have been analysed using profilometry, overhead and cross-section SEM microscopy, respectively and EDAX measurements.

With the advance of high power laser systems, there is an increasing need to dim the corresponding light field power over larger dynamic ranges. The usual means to control the attenuation of directed light use optical filters or coatings with tailored reflectance and transmittance properties. They do not provide the variability that is often required in experiments. A system is reported here that demonstrated continuous variation of the transmittance over 70 dB, using frustrated total internal reflection.

There are few papers which aim to analyze the effects of laser marking for traceability on various materials; therefore, the present paper proposes a study of the influences of such radiation processing on a titanium alloy, a vastly used material base within several industry fields. For the novelty impact, femtolaser marking has been carried out, besides the commercial nanosecond standard engraving. All marks have been analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffractometry.

Using the original thermionic vacuum arc method (TVA), carbon films with the thickness of about 2500 nm were coated on top of 200 nm tungsten films deposited on fine grain graphite substrates. The carbon/tungsten bilayers were irradiated using a terawatt laser system (TEWALAS), 360 ps and 100 fs pulse duration, 110–150 mJ pulse energy. The analysis of the selected area electron diffraction (SAED) pattern allowed the identification of rhomboedral structures corresponding to diamond. The Raman scattering measurements were also performed on the produced craters and the specific peak at 1330 cm−1 corresponding to diamond was observed. The CC sp3 bonding content increased to 39.4% in the irradiated region compared to 30.8% in the “as deposited” zone, as shown by XPS. The craters produced by the laser irradiation were morphologically studied using optical imaging and scanning electron microscopy.

We report sub-diffraction limited patterning of Si substrate surfaces by laser-initiated liquid-assisted colloidal lithography. The technique involves exposing a two-dimensional lattice of transparent colloidal particles spin coated on the substrate of interest (here Si) immersed in a liquid (e.g. methanol, acetone, carbon tetrachloride, toluene) to a single picosecond pulse of ultraviolet laser radiation. Surface patterns formed using colloidal particles with different radii in the range 195 nm ≤ R ≤ 1.5 μm and liquids with differing indices of refraction (n(liquid)) are demonstrated, the detailed topographies of which are sensitively dependent upon whether the index of refraction of the colloidal particle (n(colloid)) is greater or smaller than n liquid (i.e. upon whether the incident light converges or diverges upon interaction with the particle). The spatial intensity modulation formed by diffraction of the single laser pulse by the colloidal particles is imprinted into the Si substrate.

The paper describes a novel application of an electron beam ion trap as a plasma target facility for intense laser-plasma interaction studies. The low density plasma target (~;1013/cm3) is confined in a mobile cryogenic electromagnetic charged particle trap, with the magnetic confinement field of 1-3 T maintained by a superconducting magnet. Ion plasmas for a large variety of ion species and charge states are produced and maintained within the magnetic field and the space-charge of an energetic electron beam in the "electron beam ion trap" (EBIT) geometry. Intense laser beams (optical lasers, X-ray lasers and upcoming "X-ray free electron lasers" (XFEL)) provide strong time varying electromagnetic fields (>1012 V/cm in femto- to nano-second pulses) for interactions with electromagnetically confined neutral/non-neutral plasmas. Experimental scenarios with intense photon fields on ionization/excitation processes, the ionization balance, as well as photon polarization effects and tests with intense lasers that utilize the ion plasma target are outlined. A first test of the plasma target with the PHELIX high intensity laser at GSI is described.

For a better understanding of the structures of exotic nuclei it is of crucial importance to develop a practical microscopic theory easy to be applied to a wide range of masses. In this paper the structures and distributions of light nuclei are investigated within a microscopic correlation model. Two particle correlations are responsible for the scattering of model particles either to low momentum- or to high momentum-states. The low momentum states form the model space while the high momentum states are used to calculate the G-matrix. The three and higher order particle correlations do not play a role in the latter calculation especially if the correlations induced by the scattering operator are of sufficient short range. They modify however, via the long tail of the nuclear potential, the Slater determinant of the 6 ⩽ A ⩽ 8 particles by generating (Ap-(np-nh)) excited Slater's determinants.

Intense and stable laser operation with Ni-like Zr and Ag was demonstrated at pump energies between 2 J and 5 J energy from the PHELIX pre-amplifier section. A novel single mirror focusing scheme for the TCE x-ray laser (XRL) has been successfully implemented by the LIXAM/MBI/GSI collaboration under different pump geometries. This shows potential for an extension to shorter XRL wavelength. Generation of high quality XRL beams for XRL spectroscopy of highly charged ions is an important issue within the scientific program of PHELIX. Long range perspective is the study of nuclear properties of radioactive isotopes within the FAIR project.

X-ray laser simulations based on Ehybrid code have shown that enhanced plasma x-ray laser emission can be achieved mastering the ionization dynamics and plasma temperature using one long and two short pulses (Ursescu and Ionel, J Optoelectron Adv Mat 12:48–51, 2010). In parallel, two simple methods to generate multiple short pulses for pumping x-ray lasers were reported in conjunction with x-ray laser developments. Five to ten fold enhancement in the emission of the silver x-ray laser was demonstrated using the newly developed pump methods, when compared with the traditional one, based on a long pulse followed by one short pump pulse. An overview of these recent experiments will be presented. The possible implementation of these novel x-ray laser pumping methods at Extreme Light Infrastructure—Nuclear Physics facility will be discussed.

Seeded operation of a Neon-like Titanium plasma-based soft x-ray laser is described. The plasma amplifier is pumped using a variation of the classical grazing incidence pumping technique, combining a long low energy pulse followed by a main short pulse. Because the preformed plasma is underionized, a part of the main short pulse energy is used to ionized it to the lasing stage. Consequences of this feature on seeded laser properties are discussed.

Nous presentons des resultats recents de laser X collisionnel transitoire pompe en incidence rasante a haut taux de repetition. Ils ont ete obtenus a partir du laser de pompe Titane:Saphir 30 TW disponible sur l'installation europeenne du LLC a Lund (Suede). Nous avons demontre lors de cette experience qu'il etait possible d'obtenir en routine pres de 3 microjoule par impulsion a 18,9nm avec seulement J d'energie de pompe infrarouge. Nous avons plus particulierement etudie l'influence de l'angle de rasance sur cible de l'impulsion laser qui vient pomper le plasma, quelques centaines de picosecondes apres la premiere impulsion responsable de sa creation. Un systeme d'imagerie XUV a haute resolution nous a en effet permis d'obtenir des informations precieuses sur la pupille de sortie du laser X, comme l'energie totale dans la tache mais aussi la distance d'emission par rapport a la cible, et encore les dimensions horizontale et verticale de la source.

The high-energy high-power laser system PHELIX (Petawatt High Energy Laser for heavy Ion eXperiments) [1] is currently under construction at the Gesellschaft fuer Schwerionenforschung mbH (GSI) Darmstadt. With PHELIX GSI will offer the unique combination of a high-current, high-energy (GeV/u) heavy-ion beam with an intense laser beam. This will open the door to a variety of fundamental science issues in the field of atomic physics, plasma physics and nuclear physics. The project will gain further interest in the near future by the dramatic increase of the accelerator performance with the starting FAIR project at GSI [2]. This paper reports the current status of the project as well as the laser architecture. The proposed physics program and a first experiment carried out with PHELIX, the realization of a transient collisionally excited x-ray laser [3], will also be reviewed briefly.

We have investigated a new scheme for laser plasma transient collisional soft x-ray lasers based on the use of an additional laser to produce the preplasma. Soft x-ray emission measurements made for different solid targets are presented and discussed. A significant enhancement of the SXRL emission as compared to double-pulse single-beam grazing incidence (DGRIP) using the same pump laser is reported for 13.9- and 32.6-nm SXRL wavelengths.

To facilitate the use of the extended nuclear shell model (NSM), a F ERMI module for calculating some of its basic quantities in the framework of MAPLE is provided. The Moshinsky brackets, the matrix elements for several central and non-central interactions between nuclear two-particle states as well as their expansion in terms of Talmi integrals are easily given within a symbolic formulation. All of these quantities are available for interactive work. Program summary

We study the charge radii of exotic nuclei through nuclear calculations and isotopic-shift evaluations. The computations are performed in the framework of the dynamic-correlation model DCM for nuclei with an odd number of valence particles and in the boson dynamic-correlation model (BCDM) for those with an even number of valence particles. These nuclear models take fully into consideration the correlation between valence particles as well as between valence and core particles. Consequently, these computations may reveal feature physics which is associated to the strong correlation between the valence and the core polarized states. Moreover,we propose to analyze the obtained charge radii within the isotopic shift theory in which the electronic transitions for lithium and lithium-like ions are calculated by considering the three correlated electrons described by a method similar to the nuclear DCM model.

Energies, electromagnetic moments and transitions in light, nuclei are calculat,ed in t,he microscopic dynamic-correlation model (DCM) which is based on large correhted basis of Slateris determinants charact,erized by an increasing numbcr of core excited states. Microscopic calculations are performed for the magnetic moments and transit,ions of iBe and I3C. The magnetic moments of 6Li, 7Li, and iLi are also calculated. Further, rcsult,s obt,ained for matt,er and charge ra.dii of 7B~ and iBe arc reported. The overall results obt#ained for these light odd- and even-nuclei show that, t,he correct treatment of the Pauli principle and the diagonalizat,ion of large dimensional spaces are not compat,ible with the simple picture generatled by cluster models.

Extreme Light Infrastructure-Nuclear Physics (ELI-NP), to become operational in 2019, is a new Research Center built in Romania that will use extreme electromagnetic fields for nuclear physics research. The ELI-NP facility will combine two large equipments with state-of-the-art parameters, namely a 2 × 10 PW high-power laser system and a very brilliant gamma-beam system delivering beams with energies up to 19.5 MeV. The laser and gamma-beam systems under construction and typical proposed first-phase experiments are described.

International audience; The measurement of energy spectra of neutrons and gamma rays emitted by nuclei, together with charge particles spectroscopy, are the main tools for understanding nuclear phenomena occurring also in high power laser driven experiments. However, the large number of particles emitted in a very short time, in particular the strong X-rays flash produced in laser-target interaction, impose adaptation of technique currently used in nuclear physics experiment at accelerator based facilities. These aspects are discussed (Section 1) in the context of proposed studies at high power laser system of ELI-NP. Preliminary results from two experiments performed at Titan (LLNL) and ELFIE (LULI) facilities using plastic scintillators for neutron detection (Section 2) and LaBr3 (Ce) scintillators for gamma detection (Section 3) are presented demonstrating the capabilities and the limitations of the employed methods. Possible improvements of these spectroscopic methods and their proposed implementation at ELI-NP will be discussed as well in the last section.

An alternative, novel multiple pulse generation scheme was implemented directly after the optical compressor output of an x-ray pump laser. The new method uses a polarization sensitive thin film beam splitter and a half-wavelength wave plate for tuning the energy ratio in the multiple short pulses. Based on this method, an extensive study was made of the running parameters for a grazing incidence pumped silver x-ray laser (XRL) pumped with a long pulse of 145 mJ in 6 ns at 532 nm and up to 1.45 J in few picoseconds at 810 nm. Fivefold enhancement in the emission of the silver XRL was demonstrated using the new pump method.

Carbon–tungsten layers deposited on graphite by thermionic vacuum arc (TVA) were directly irradiated with a femtosecond terawatt laser. The morphological and structural changes produced in the irradiated area by different numbers of pulses were systematically explored, both along the spots and in their depths. Although micro-Raman and Synchrotron-x-ray diffraction investigations have shown no carbide formation, they have shown the unexpected presence of embedded nano-diamonds in the areas irradiated with high fluencies. Scanning electron microscopy images show a cumulative effect of the laser pulses on the morphology through the ablation process. The micro-Raman spatial mapping signalled an increased percentage of sp3 carbon bonding in the areas irradiated with laser fluencies around the ablation threshold. In-depth x-ray photoelectron spectroscopy investigations suggested a weak cumulative effect on the percentage increase of the sp2-sp3 transitions with the number of laser pulses just for nanometric layer thicknesses.

The study presented here has proposed a way to introduce the NIB mechanism in the complex refractive index formalism for understanding the propagation of short light pulses in plasmas. It was applied to the specific case of GRIP XRL efficiency analysis. However, it could also be useful for a broader range of applications related to the behaviour of short pulses in plasmas, such as plasma mirrors and the propagation of ultra-short light pulses in plasma channels. The complex refractive index formalism was applied to two specific XRL arrangements. In the first, GRIP XRLs, the results show that at very small grazing angles little energy is deposited in the plasma due to the reduced opacity. Slightly larger grazing angles, in the range 25–30° instead of 18° for a wavelength of 1.054 µm, and longer, but still short, pulses can circumvent the opacity problem and increase the XRL efficiency since the pumping energy is then efficiently deposited in the pre-plasma. In the second case, sub-10nm XRL systems, the required pump energy is significantly higher, around 20 J for a Ni-like lanthanum XRL to a few kilojoules for water-window XRLs. Increasing the opacity of the plasma by tuning the plasma parameters can significantly increase the temperature of the plasma formed by a short pulse and reduce the pumping energy requirements, making shorter wavelength XRLs possible at limited pump energies.

Optical near field enhancements in the vicinity of particles illuminated by laser light are increasingly recognized as a powerful tool for nanopatterning applications, but achieving sub-wavelength details from the near-field distribution remains a challenge. Here we present a quantitative analysis of the spatial modulation of the near optical fields generated using single 8 ps, 355 nm (and 532 nm) laser pulses around individual colloidal particles and small close packed arrays of such particles on silicon substrates. The analysis is presented for particles in air and, for the first time, when immersed in a range of liquid media. Immersion in a liquid allows detailed exploration of the effects on the near field of changing not just the magnitude but also the sign of the refractive index difference between the particle and the host medium. The level of agreement between the results of ray tracing and Mie scattering simulations, and the experimentally observed patterns on solid surfaces, should encourage further modelling, predictions and demonstrations of the rich palette of sub-wavelength surface profiles that can be achieved using colloidal particles immersed in liquids.

Extreme Light Infrastructure (ELI) Pan-European facility initiative represents a major step forward in quest for extreme electromagnetic fields. Extreme Light Infrastructure – Nuclear Physics (ELI-NP) is one of the three pillars of the ELI facility, that aims to use extreme electromagnetic fields for nuclear physics and quantum electrodynamics research. At ELI-NP, high power laser systems together with a very brilliant gamma beam are the main research tools. Their targeted operational parameters are described. The related experimental areas are presented, together with the main directions of the research envisioned.