Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto-and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds (1 attosecond=1 as=10 −18 s), which is comparable with the optical field. For comparison, the revolution of an electron on a 1s orbital of a hydrogen atom is ∼ 152 as. On the other hand, the second branch involves the manipulation and engineering of mesoscopic systems, such as solids, metals and dielectrics, with nanometric precision. Although nano-engineering is a vast and well-established research field on its own, the merger with intense laser physics is relatively recent. In this report on progress we present a comprehensive experimental and theoretical overview of physics that takes place when short and intense laser pulses interact with nanosystems, such as metallic and dielectric nanostructures. In particular we elucidate how the spatially inhomogeneous laser induced fields at a nanometer scale modify the laser-driven electron dynamics. Consequently, this has important impact on pivotal processes such as above-threshold ionization and high-order harmonic generation. The deep understanding of the coupled dynamics between these spatially inhomogeneous fields and matter configures a promising way to new avenues of research and applications. Thanks to the maturity that attosecond physics has reached, together with the tremendous advance in material engineering and manipulation techniques, the age of atto-nano physics has begun, but it is in the initial stage. We present thus some of the open questions, challenges and prospects for experimental confirmation of theoretical predictions, as well as experiments aimed at characterizing the induced fields and the unique electron dynamics initiated by them with high temporal and spatial resolution.

Positioning probe molecules at electromagnetic hot spots with nanometer precision is required to achieve highly sensitive and reproducible surfaceenhanced Raman spectroscopy (SERS) analysis. In this article, molecular positioning at plasmonic nanogaps is reported using a high aspect ratio (HAR) plasmonic nanopillar array with a controlled surface energy. A largearea HAR plasmonic nanopillar array is generated using a nanolithographyfree simple process involving Ar plasma treatment applied to a smooth polymer surface and the subsequent evaporation of metal onto the polymer nanopillars. The surface energy can be precisely controlled through the selective removal of an adsorbed self-assembled monolayer of low surfaceenergy molecules prepared on the plasmonic nanopillars. This process can be used to tune the surface energy and provide a superhydrophobic surface with a water contact angle of 165.8° on the one hand or a hydrophilic surface with a water contact angle of 40.0° on the other. The highly tunable surface wettability is employed to systematically investigate the effects of the surface energy on the capillary-force-induced clustering among the HAR plasmonic nanopillars as well as on molecular concentration at the collapsed nanogaps present at the tops of the clustered nanopillars.

Thin liquid sheet jet flows in vacuum provide a new platform for performing experiments in the liquid phase, for example X-ray spectroscopy. Micrometer thickness, high stability and optical flatness are the key characteristics required for successful exploitation of these targets. A novel strategy for generating sheet jets in vacuum is presented in this article. Precision nozzles were designed and fabricated using high resolution (0.2 µm) 2-photon 3D printing and generated 1.49±0.04 µm thickness, stable and <λ/20-flat jets in isopropanol under normal atmosphere and under vacuum at 5×10 −1 mbar. The thin sheet technology also holds great promise for advancing the fields of high harmonic generation in liquids, laser acceleration of ions as well as other fields requiring precision and high repetition rate targets.

cient solar cells by external recycling of photon emission is presented predicated on the strategy of increasing cell open-circuit voltage by reducing radiative recombination. It is equivalent to restricting the angular range of photon emission, and can only be effective in photovoltaics with high external luminescent efficiency. This has precluded the voltage enhancement from being observable in today's photovoltaic technologies. As shown here, however, it is attainable with the latest generation of champion single-junction one sun thin-film GaAs cells. The measurements are understandable in terms of basic photovoltaic thermodynamics.

A challenge for design, testing and fabrication of nano-structured chemical sensors is the fabrication of mm 2 size arrays of nano-structures in a reasonable time. Herein, we introduce and show how direct laser writing (DLW) in positive-tone photo-resists, followed by lift-off process can be used for fast fabrication (up to three-times faster than comparable Electron Beam lithography system) of arrays of nano-scale plasmonic structures with a great level of control over the design and dimensions of the nano-structures. We demonstrate the function of nano-structured arrays, fabricated by various DLW approaches, with surface enhanced infra-red absorption (SEIRA) detection of nine vibrational modes of PMMA. We also discuss the tunability of the plasmonic resonance -and hence the spectral detection range -by alteration of the size and array parameters of the nanostructures, and demonstrate the flexibility of this fabrication method by showing devices made of various substrate and antennas materials. KeywordsChemical detection, SEIRA , Plasmonic sensors, Direct laser writing, Nano-fabrication When adsorbed near or on nano-structured metal surfaces, molecules can demonstrate a remarkable change in their optical properties with applications in surface enhanced spectroscopies. Two notable examples for such detection methods are surface enhanced Raman scattering (SERS) 1-4 , and surface enhanced infrared absorption (SEIRA) [4][5][6][7][8][9][10][11][12][13][14][15][16] . In SEIRA spectroscopy, metallic and dielectric nanoantennas that exhibit plasmonic resonances in the Infra-Red (IR) regime are used to intensify the IR absorption signal of known vibrational modes of molecules, so that even small amount of analytes can be identified [4][5][6][7][8][9][10][11][12][13][14][15][16] . The improved detection originates from the excitation of localized surface plasmon resonances (LSPRs) -charge oscillations on the surface of the nano-structured surface -which give rise to a strong local electric field at the vicinity of the nanostructures and enhanced coupling between the textured surface and the vibrational modes of the adsorbed molecules. The enhancement is strongest when the plasmonic resonance of the nano-structures matches the spectral position of the vibrational fingerprints. This implies that that the spectral range at which improved detection is possible and the enhancement factor of the chemical sensor depend on sensor materials 12,15,16 (both of the nanostructures and the substrate), and the shape 13,14,[17][18][19] and dimensions of individual structures 8,12,16,18 and the spacing between them 10 .