Recent advances in attosecond science in combination with the well-established techniques of nanofabrication have led to the new research field of attosecond nanophysics. One central goal is the characterization and manipulation of electromagnetic fields on the attosecond and nanometer scale. This has so far remained challenging both theoretically and experimentally. One major obstacle is the inhomogeneity of the electric fields. We present a general model below, which allows the description of attosecond streaking in near fields. It allows the classification into different regimes as well as the reconstruction of the electric fields at the surface. In addition, we discuss the case of parallel polarization of the streaking fields to the surface, which has so far not been considered for attosecond streaking from metallic surfaces. Finally, we review recent measurements of the electric field and response function of a gold nanotaper. Our results are highly relevant for future attosecond streaking experiments in inhomogeneous fields.

The application of ultra-short waveform-controlled laser fields to nanostructured materials enables the generation of localized near-fields with well-defined spatiotemporal field evolution. The optical fields that can be tailored on sub-wavelength spatial and attosecond temporal scales have a high potential for the control of ultrafast processes at the nanoscale, with important implications for laser-driven electron acceleration, extreme ultraviolet (XUV) light generation, and nanoscale electronics operating at optical frequencies.

The dissociative ionization of toluene initiated by a few-cycle laser pulse as a function of the carrier envelope phase (CEP) is investigated using single-shot velocity map imaging. Several ionic fragments, CH3+, H2+, and H3+, originating from multiply charged toluene ions present a CEP-dependent directional emission. The formation of H2+ and H3+ involves breaking C-H bonds and forming new bonds between the hydrogen atoms within the transient structure of the multiply charged precursor. We observe appreciable intensity-dependent CEP-offsets. The experimental data are interpreted with a mechanism that involves laser-induced coupling of vibrational states, which has been found to play a role in the CEP-control of molecular processes in hydrocarbon molecules, and appears to be of general importance for such complex molecules.

The excitation of nanoscale near-fields with ultrashort and intense laser pulses of well-defined waveform enables strongly spatially and temporally localized electron emission, opening up the possibility for the generation of attosecond electron pulses. Here, we investigate the electron photoemission from isolated nanoparticles of different materials in few-cycle laser fields at intensities where the Coulomb field of the ionized electrons and residual ions significantly contribute to the electron acceleration process. The dependences of the electron cut-off energy on the material's dielectric properties and electron binding energy are investigated systematically in both experiments and semi-classical simulations. We find that for sufficiently high near-field intensities the material dependence of the acceleration in the enhanced near-fields is quenched by many-particle charge-interaction.