Attosecond XUV sources generation from polarized gating two-color chirped pulse

2015 ◽  
Vol 29 (21) ◽  
pp. 1550111 ◽  
Author(s):  
Liqiang Feng ◽  
Hang Liu ◽  
Tianshu Chu
Keyword(s):  
High Order ◽  
Promising Method ◽  
Polarization Angle ◽  
Single Quantum ◽  
Experimental Realization ◽  
Chirped Pulse ◽  
Laser Parameters ◽  
High Order Harmonic ◽  
Attosecond Pulses ◽  
Cycle Pulse

A promising method to generate the attosecond XUV sources from the high-order harmonic has been theoretically presented by controlling the polarized gating two-color chirped pulse. The results show that with the introduction of the chirps, the harmonic has been remarkably extended. Moreover, the harmonic interferences are very sensitive to the polarization angle between the two lasers. Particularly, when the polarization angle is equal to [Formula: see text], the supercontinuum with a single quantum path contribution is achieved, and a series of isolated attosecond pulses with the duration of 33 as are directly obtained. Further, by testing the influences of other laser parameters on the supercontinuum, we found that this polarized two-color chirped scheme can also be achieved in the multi-cycle pulse region, which is much better for experimental realization.

Generation of Broadband Supercontinuum and Isolated Attosecond Pulse in a Chirped Two-Colour Laser Field

2013 ◽  
Vol 68 (6-7) ◽  
pp. 461-474
Author(s):  
Gang-Tai Zhang
Keyword(s):  
Laser Field ◽  
Polarization Angle ◽  
Single Quantum ◽  
High Order Harmonic Generation ◽  
Chirped Pulse ◽  
High Order Harmonic ◽  
Chirped Pulses ◽  
Isolated Attosecond Pulse ◽  
Linearly Polarized ◽  
Spectrum Intensity

We present a theoretical investigation of high-order harmonic generation in a chirped two-colour laser field, which is synthesized by an 800 nm fundamental chirped pulse and a 1200 nm subharmonic chirped pulse. With the introduction of a polarization angle, both the harmonic cutoff is significantly extended and the spectrum intensity is effectively enhanced compared with the orthogonally polarized chirped two-colour field. When the polarization angle between the two chirped pulses is less than or equal to 0:27p, the broadband supercontinuum with a single quantum path contribution is achieved, and then isolated attosecond pulses with the duration of about 40 as are directly obtained, which are all linearly polarized. In addition, the influences of other laser parameters on the supercontinuum are also investigated.

scholarly journals Focusing Properties of High-Order Harmonics

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Maria Hoflund ◽  
Jasper Peschel ◽  
Marius Plach ◽  
Hugo Dacasa ◽  
Kévin Veyrinas ◽  
...  
Keyword(s):  
Extreme Ultraviolet ◽  
Laser System ◽  
High Order ◽  
Harmonic Order ◽  
High Order Harmonic Generation ◽  
High Order Harmonic ◽  
Attosecond Pulses ◽  
Small Focus ◽  
The Individual ◽  
Focusing Properties

Many applications of the extreme ultraviolet (XUV) radiation obtained by high-order harmonic generation (HHG) in gases require a small focus area in order to enable attosecond pulses to reach a high intensity. Here, high-order harmonics generated in Ar with a multiterawatt laser system in a loose focusing geometry are focused to a few micrometers using two toroidal mirrors in a Wolter configuration with a high demagnification factor. Using a knife-edge measurement technique, we determine the position and size of the XUV foci as a function of harmonic order. We show that the focus properties vary with harmonic order and the generation conditions. Simulations, based on a classical description of the harmonic dipole phase and assuming that the individual harmonics can be described as Gaussian beams, reproduce the experimental behavior. We discuss how the generation geometry affects the intensity and duration of the focused attosecond pulses.

Generation of high-order harmonics and attosecond pulses

2019 ◽  
pp. 326-342
Author(s):  
Anne L’Huillier
Keyword(s):  
Extreme Ultraviolet ◽  
High Order ◽  
Intense Laser ◽  
Single Atom ◽  
Light Pulses ◽  
High Order Harmonic ◽  
Attosecond Pulses ◽  
Intense Laser Radiation ◽  
Atom Level ◽  
The Time Domain

The interaction of atoms with intense laser radiation leads to the generation of high-order harmonics of the laser field. In the time domain, this corresponds to a train of pulses in the extreme ultraviolet range and with attosecond duration. The first section introduces the physics of high-order harmonic generation and attosecond pulses on the single atom level while the second section discusses phase matching and propagation effects. The attosecond time scale is that of the electron motion in atoms and molecules. Attosecond light pulses are used to study, for example, the dynamics of atomic or molecular photoionization. The third section will present an interferometric method developed for measuring attosecond pulses and discuss some of the applications, in particular concerning photoionization dynamics.

Multiple-acceleration in “W” waveform structure for high-order harmonic improvement

2019 ◽  
Vol 28 (04) ◽  
pp. 1950037 ◽  
Author(s):  
Hui Liu ◽  
Yi Li ◽  
Hang Liu ◽  
A. Yuanzi Feng ◽  
Liqiang Feng ◽  
...  
Keyword(s):  
Fourier Transformation ◽  
Initial Velocity ◽  
Text Structure ◽  
High Order ◽  
Acceleration Process ◽  
Half Cycle ◽  
High Order Harmonic Generation ◽  
High Order Harmonic ◽  
Text Structures ◽  
Cycle Pulse

Generally, high-order harmonic generation (HHG) from atoms and molecules can be explained by the “ionization-acceleration-recombination” model and the classical results are agreement with the quantum results. In this paper, we report a multiple-acceleration process in the “[Formula: see text]” waveform structure. It is found that due to the nonzero initial velocity in the multiple-acceleration process, the emitted photon energies from the quantum results are larger than those from the classical results. Moreover, with the optimization of this “[Formula: see text]” waveform structure, much more energy can be obtained for the accelerated electron, thus leading to the improvement of the HHG. Further, with the introduction of a half-cycle pulse, the effects of the two “[Formula: see text]” structures in the “[Formula: see text]” structure on the HHG are discussed. It shows that the latter “[Formula: see text]” structure plays the more important role in HHG modulation. Finally, through the Fourier transformation of the spectral continuum, a number of sub-40 as pulses with intensity enhancements of 1 order and 2 orders of magnitudes can be obtained, respectively.

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