High harmonic generation (HHG) opens a window on the fundamental science of strong-field light-mater interaction and serves as key building block for attosecond optics metrology. Resonantly enhanced HHG from hot spots in nanostructures is an attractive route to overcoming well-known limitations gases bulk solids. We demonstrate nanoscale platform highly efficient driven by strong mid-infrared l...

We present a study of photon statistics associated with high-order harmonic generation (HHG) involving one-mode and intermodal correlations the high photons. The aim paper is to give insight into nonclassical properties modes. To this end, we use simplified model describing an elementary quantum emitter: two-level atom. While material system extremely in description, conclusions methods may be ...

Highly nonlinear optical phenomena can provide access to properties of electronic systems which are otherwise difficult through conventional linear spectroscopies. In particular, high-harmonic generation (HHG) in crystalline solids is strikingly different from that atomic gases, and it enables us such as the band structure, Berry curvature, valence electron density. Here, we show polarization-r...

High-harmonic generation (HHG) normally requires a careful adjustment of the driving laser intensity (typically $10^{14} - 10^{15}$ W/cm$^2$) and gas medium parameters to enable good phase matching conditions. In contrast with conventional wisdom, we present experimental results indicating phase-matched HHG in all rare gases, using high-density driver around $10^{16}$ W/cm$^2$. The are corrobor...

High harmonic generation (HHG) enables coherent extreme-ultraviolet (XUV) radiation with ultra-short pulse duration in a table-top setup. This has already enabled plethora of applications. Nearly all these applications would benefit from high photon flux to increase the signal-to-noise ratio and decrease measurement times. In addition, shortest pulses are desired investigate fastest dynamics fi...

Intense-field many-body S-matrix theory (IMST) provides a systematic ab initio approach to investigate the dynamics of atoms and molecules interacting with intense laser radiation. We review the derivation of IMST as well as its diagrammatic representation and point out its advantage over the conventional ‘prior’ and ‘post’ expansions which are shown to be special cases of IMST. The practicalit...

To produce extreme ultraviolet radiation via high harmonic generation (HHG) in rare gases, light intensities in excess of 1014 W/cm 2 are required. Usually such high intensity are obtained by parametric amplification of laser pulses, which in turn reduces the pulse repetition rate to a few kHz. Given that the HHG process is inherently inefficient, with conversion ratios less than 10-5, only a s...

We present our attoline which is a versatile attosecond beamline at the Ultrafast Laser Physics Group at ETH Zurich for attosecond spectroscopy in a variety of targets. High-harmonic generation (HHG) in noble gases with an infrared (IR) driving field is employed to generate pulses in the extreme ultraviolet (XUV) spectral regime for XUV-IR cross-correlation measurements. The IR pulse driving th...

High harmonic generation (HHG) spectroscopy has opened up a new frontier in ultrafast science, where electronic dynamics can be measured on an attosecond time scale. The strong laser field that triggers the high harmonic response also opens multiple quantum pathways for multielectron dynamics in molecules, resulting in a complex process of multielectron rearrangement during ionization. Using co...

The sensitivities of high-harmonic generation (HHG) and strong-field ionization (SFI) to coupled electronic and nuclear dynamics are studied, using the nitric oxide (NO) molecule as an example. A coherent superposition of electronic and rotational states of NO is prepared by impulsive stimulated Raman scattering and probed by simultaneous detection of HHG and SFI yields. We observe a fourfold h...