Multichannel high-order harmonic generation from solids

Du, Tao-Yuan; Tang, Dong; Huang, Xiangyong; Bian, Xue-Bin

doi:10.1103/physreva.97.043413

Cited by 38 publications

(23 citation statements)

References 52 publications

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“…While much of the microscopic HHG dynamics can be understood in terms of a two-band picture [14,16,17,21,[32][33][34] involving a filled valence band and a single conduction band, a number of works have highlighted the role of multiple bands [19,[35][36][37][38][39]. In particular, it has been experimentally demonstrated that multiple bands were responsible for nonintuitive harmonic waveforms in bulk GaSe [40], the emergence of multiple plateaus in rare-gas solids [41], and yield enhancement of different harmonic regions in MgO [42].…”

Section: Introductionmentioning

confidence: 99%

Signatures of multi-band effects in high-harmonic generation in monolayer MoS$_2$

Yue¹,

Hollinger²,

Uzundal³

et al. 2021

Preprint

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High-harmonic generation (HHG) in solids has been touted as a way to probe ultrafast dynamics and crystal symmetries in condensed matter systems. Here, we investigate the polarization properties of high-order harmonics generated in monolayer MoS 2 , as a function of crystal orientation relative to the mid-infrared laser field polarization. At several different laser wavelengths we experimentally observe a prominent angular shift of the parallel-polarized odd harmonics for energies above approximately 3.5 eV, and our calculations indicate that this shift originates in subtle differences in the recombination dipole strengths involving multiple conduction bands. This observation is material specific and is in addition to the angular dependence imposed by the dynamical symmetry properties of the crystal interacting with the laser field, and may pave the way for probing the vectorial character of multi-band recombination dipoles.

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Section: Introductionmentioning

confidence: 99%

Signatures of multi-band effects in high-harmonic generation in monolayer MoS$_2$

Yue¹,

Hollinger²,

Uzundal³

et al. 2021

Preprint

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“…In the early studies of intense laser and solid interaction, the DBO was considered as one of the main mechanisms of generating solid harmonics [33][34][35] . For multiple band systems, recent works 36,37 show that a coherent superposition of dynamical Bloch oscillations and Zener tunneling, i.e., Bloch-Zener oscillation (BZO), has significant influences on the HHG. This is because the DBO changes the group velocity of carriers rapidly, which affects the recombination of electron-hole pairs 38 .…”

Section: Introductionmentioning

confidence: 99%

Ellipticity dependence transition induced by dynamical Bloch oscillations

Zhang

Zhou

et al. 2019

Phys. Rev. B

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The dependence of high-harmonic generation (HHG) on laser ellipticity is investigated using a modified ZnO model. In the driving of relatively weak field, we reproduce qualitatively the ellipticity dependence as observed in the HHG experiment of wurtzite ZnO. When increasing the field strength, the HHG shows an anomalous ellipticity dependence, similar to that observed experimentally in the single-crystal MgO. With the help of a semiclassical analysis, it is found that the key mechanism inducing the change of ellipticity dependence is the interplay between the dynamical Bloch oscillation and the anisotropic band structure. The dynamical Bloch oscillation contributes additional quantum paths, which are less sensitive to ellipticity. The anisotropic band-structure make the driving pulse with finite ellipticity be able to drive the pairs to the band positions with larger gap, which extends the harmonic cutoff. The combination of these two effects leads to the anomalous ellipticity dependence. The result reveals the importance of dynamical Bloch oscillations for the ellipticity dependence of HHG from bulk ZnO.

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“…Note that breaking the lattice periodicity increases the theoretical complexity, since Bloch's theorem becomes inapplicable and one cannot simply use periodic boundary conditions in calculations. Previous theoretical investigations on HHG in solids are typically based on the semiconductor Bloch equations [12,[20][21][22][23] or the time-dependent Schrödinger equation in single-active-electron (SAE) models [24][25][26][27][28][29][30][31]. In pursuit of going beyond the SAE models, there are also theoretical works that employ many-electron approaches such as the time-dependent density-functional theory (TDDFT) [32][33][34][35][36][37] and the time-dependent Hartree-Fock theory [38].…”

Section: Introductionmentioning

confidence: 99%

High-order harmonic generation in imperfect crystals

Hansen

Madsen

2019

Phys. Rev. A

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High-order harmonic generation (HHG) in imperfect crystals, where the disorder is modeled by random shifts of the ionic positions, is studied using time-dependent density-functional theory. When irradiated by midinfrared laser pulses, the disorder-free system produces HHG spectra with two plateaus. Compared with the disorder-free system, disordered systems are found to emit suppressed harmonics in the first plateau region and enhanced harmonics in the second plateau region. The suppression of harmonics in the first plateau becomes less pronounced when decreasing the displacement of the nuclei, while the enhancement in the second plateau region is insensitive to the range of the ionic displacement. We have confirmed these findings for many different disordered sample systems and for different laser field strengths. The increase of the HHG signals in the second plateau region is proposed to stem from a change of the dynamics in the system, evidenced by the transition matrix elements between the field-free Kohn-Sham orbitals. In addition, a time-frequency profile of HHG spectra shows that the emission of harmonics is less regular in the time domain for a disordered system than for the disorder-free system.

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Multichannel high-order harmonic generation from solids

Cited by 38 publications

References 52 publications

Signatures of multi-band effects in high-harmonic generation in monolayer MoS$_2$

Signatures of multi-band effects in high-harmonic generation in monolayer MoS$_2$

Ellipticity dependence transition induced by dynamical Bloch oscillations

High-order harmonic generation in imperfect crystals

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