Related papers: High-harmonics and isolated attosecond pulses from…
We study theoretically and experimentally High Harmonic Generation (HHG) using two non collinear driving fields focused in gases. We show that these two fields form a non stationary blazed active grating in the generation medium. The…
In recent publications, it has been shown that high-order harmonic generation can be manipulated by employing a time-delayed attosecond pulse train superposed to a strong, near-infrared laser field. It is an open question, however, which is…
Synchronous extreme ultraviolet (XUV) and single-cycle terahertz (THz) bursts are generated in argon plasma induced by intense two-color femtosecond laser pulses. Correlations between the intensity of the even and odd high-harmonics and the…
We experimentally demonstrate generation of strong narrow-bandwidth emissions with excellent coherent properties at ~391 nm and ~428 nm from molecular ions of nitrogen inside a femtosecond filament in air by an orthogonally polarized…
We carried out a joint theoretical and experimental study of the polarization of high-order harmonics generated from ZnO by intense infrared laser pulses. Experimentally we found that the dependence of parallel and perpendicular…
High harmonic generation in benzene is studied using a mixed quantum-classical approach in which the electrons are described using time-dependent density functional theory while the ions move classically. The interaction with both…
High-harmonic generation (HHG) in solids has typically been explored in transparent dielectrics and semiconductors. Metals have long been dismissed due to their strong reflectivity at infrared wavelengths. Here, we demonstrate HHG from…
At the core of attosecond science lies the ability to generate laser pulses of sub-femtosecond duration. In tabletop devices the process relies on high-harmonic generation, where a major challenge is to obtain high yields and high cutoff…
We study the temporal and spatial dynamics of the large amplitude and frequency modulation that can be induced in an intense, few cycle laser pulse as it propagates through a rapidly ionizing gas. Our calculations include both single atom…
We present the first direct experimental confirmation of attosecond pulse generation in the hard X-ray regime with a free-electron laser. Our experiment is based on measurements of a nonlinear optical phenomenon known as amplified…
Attosecond pulses are fundamental for the investigation of valence and core-electron dynamics on their natural timescale. At present the reproducible generation and characterisation of attosecond waveforms has been demonstrated only through…
High-order harmonic generation (HHG) has become a standard technique for producing attosecond XUV pulses in the laboratory, yet the high flux necessary for nonlinear XUV photoionization remains accessible to only a few research groups.…
We demonstrate unexpectedly strong second harmonic generation (SHG) in Argon gas by use of spatiotemporally focused (SF) femtosecond laser pulses. The resulting SHG by the SF scheme at a 75 cm distance shows a significantly enhanced…
We propose a concept for production of high power coherent attosecond pulses in X-ray range. An approach is based on generation of 8th harmonic of radiation in a multistage HGHG FEL (high gain high harmonic free electron laser)…
The mechanism underlying high harmonic generation (HHG) in gases has been well clarified, characterizing attosecond pulse trains (APT) in the time domain, significantly advances the synthesis of isolated attosecond pulse (IAP). However, the…
Generating energetic femtosecond mid-IR pulses is crucial for ultrafast spectroscopy, and currently relies on parametric processes that, while efficient, are also complex. Here we experimentally show a simple alternative that uses a single…
We study the influence of the pulse duration on high harmonic generation (HHG) with exploring a wide laser-parameter region theoretically. Previous studies have showed that for high laser intensities near to the saturation ionization…
In this work we study the impact of chromatic focusing of few-cycle laser pulses on high-order harmonic generation (HHG) through analysis of the emitted extreme ultraviolet (XUV) radiation. Chromatic focusing is usually avoided in the…
Coherent control over electron dynamics in atoms and molecules using high-intensity circularly-polarized laser pulses gives rise to current loops, resulting in the emission of magnetic fields. We propose and demonstrate with ab-initio…
The dissociation dynamics of diatomic molecules interacting with (near) optical laser pulses of different duration is investigated by an elaborate discussion of the electric field of the laser and by a direct solution of the time-dependent…