Nano-plasmonic-pump-probe effect on the intensity enhancement of attosecond pulse from hydrogen molecular ion

Abstract

An effective scheme to extend the harmonic cutoff and enhance the harmonic yield from ion by using nano-plasmonic-pump-probe technology has been proposed. The essence of the present scheme is to use the pump pulse to steer to the multi-photon-resonance-ionization region, where the ionization probability can be remarkably enhanced. Then, a sequential probe pulse with a proper delay time can enhance the harmonic yield. Furthermore, by properly choosing the injected position of and by properly adding a controlling pulse, a single harmonic emission event with a broader harmonic plateau can be obtained. Finally, by the Fourier transformation of the selected harmonics on the harmonic plateau, a single 38 as pulse with intensity enhancement of 400 times can be obtained.

Generation of high-intensity single attosecond x-ray pulses with multi-laser beam superposition

“…As a result, the HRE of P 3 from E(t) > 0 a.u. can be remarkably extended [66,67], as shown in figure 17(d). However, due to the lower ionization probability on the rising part of the laser field, the intensity of P 3 is very weak, which is responsible for the lower efficiency of the supercontinuum on the HHG spectrum.…”

Half-cycle waveform control for producing a broad and intense harmonic spectral continuum and an isolated attosecond pulse

“…For instance, in atomic systems, use of the ultraviolet (UV) resonance ionization scheme [20,21], superposition of the initial states [22,23] and the high Rydberg initial state [24,25], can enhance the harmonic yield. In H 2 + and its isotopic molecule systems, the charge resonance enhanced ionization scheme is an effective method for improving the harmonic intensity [26][27][28].…”

“…As can be seen, if one wants to obtain a broad and intense harmonic spectral region, proper control of the ionization and acceleration processes is necessary. However, in previous investigations [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], control of the ionization and acceleration processes of the free electron has always been discussed separately. Thus, in this paper, the harmonic emission process in the half-cycle waveform has been well controlled by proper choice of the half-cycle waveform.…”

Rydberg electron focused by Coulomb potential to enhance high-order harmonic generation via the chirped laser

“…For both spectroscopic applications and the optimization of attosecond pulses, it is necessary to increase the cut-off frequency and the conversion efficiency of the HHG. A lot of methods have been performed to achieve it, such as the twocolor laser field and the nano-plasmonic enhancement field [20][21][22][23][24][25]. Since the ponderomotive energy is proportional to the square of the wavelength of the driving field (U p ∝λ 2 ) according to the three-step model, the long-wavelength laser field, such as mid-infrared laser field, was extensively introduced to be the driving field in order to improve the cut-off frequency of the HHG [26][27][28][29][30][31].…”