Revealing the giant resonance in Xe via HHG with sub-two cycle 1.8 \u3bcm laser pulses

Recent advances in optical parametric amplification (OPA) based few-cycle pulse generation at 1.8 \u3bcm wavelength led to the discovery of multi-electron correlation effects in high harmonic generation (HHG), in particular the giant resonance in Xe. The novel scheme for sub-two cycle pulse generation rests upon nonlinear propagation of OPA pulses in a hollow-core fiber and subsequent compression solely by linear propagation through Fused Silica which exhibits anomalous dispersion [1]. The spectral phase introduced by self-phase modulation and self-steepening cancels material dispersion up to third order to provide an ideal laser source for HHG in gases with low ionization potential. \ua9 2011 IEEE.Peer reviewed: YesNRC publication: Ye

Studying the electronic structure of molecules with high harmonic spectroscopy

High harmonic spectroscopy is a tool to study the valence electronic structure of atoms and molecules. It uses the techniques of high harmonic generation, in which a femtosecond laser ionizes the gas sample and XUV radiation is emitted in the forward direction. The XUV intensity, phase and polarization contain information about the orbital from which an electron was removed by the laser. High harmonic spectroscopy reveals details of electron-electron interactions, motion of electronic wave packets, and can follow a chemical reaction. \ua9 Springer-Verlag Berlin Heidelberg 2013.Peer reviewed: YesNRC publication: Ye

Theory of Attosecond Pulse Generation

This chapter will discuss the theoretical aspects of producing attosecond pulses via the process of high harmonic generation driven by an intense infrared laser pulse. We will discuss the generation of attosecond pulses both at the single atom and at the macroscopic level, including a discussion of phase matching. Our goal is to broaden the understanding of attosecond pulse generation beyond the single atom level, where one thinks about the emission in terms of the laser-atom interaction alone, to include macroscopic aspects of this process. © Springer-Verlag Berlin Heidelberg 2013