Article
Chemistry, Analytical
Abdelmalek Taoutioui, Hicham Agueny
Summary: In this study, a control scheme using an infrared single-cycle pulse to enhance the efficiency of high-order harmonic generation induced by an intense near-infrared laser pulse was proposed and numerically implemented. The combined pulses were shown to produce high-energy plateaus and extend the harmonic cutoff frequency, leading to high-momentum electron recollisions. The directionality of emitted electrons can be controlled by the infrared single-cycle field, and the emerged plateaus can be manipulated by adjusting the relative phase between the two pulses and their wavelengths.
Article
Chemistry, Multidisciplinary
Yun Zhao, Zhaoxi Chen, Cheng Wang, Yuanmu Yang, Hong-Bo Sun
Summary: In this experiment, efficient second-harmonic generation (SHG) and high-harmonic generation (HHG) were demonstrated from a LiNbO3 metasurface enhanced by guided-mode resonance. The metasurface showed high SHG efficiency and a wide range of HHG. This work may enable the development of compact coherent white-light sources in the deep ultraviolet region for spectroscopy and imaging applications.
Article
Physics, Multidisciplinary
Jia-Qi Liu, Xue-Bin Bian
Summary: Studying high-order harmonic generation in Fibonacci quasicrystals reveals the presence of multi-channel emissions with higher yield and broader spectral range compared to crystals, paving the way for understanding and controlling HHG in quasicrystals and potentially leading to a shorter and stronger attosecond light source based on compact solids.
PHYSICAL REVIEW LETTERS
(2021)
Article
Optics
O. Hort, A. Dubrouil, M. A. Khokhlova, D. Descamps, S. Petit, F. Burgy, E. Mevel, E. Constant, V. V. Strelkov
Summary: A new regime of coherent XUV emission has been observed, showing potential for higher XUV intensity crucial for applications. The study explains the process of high-order parametric generation, involving the combined emission of THz and XUV photons with robust phase matching against ionization. This provides a way to use higher-energy driving pulses for generating more XUV photons.
Article
Optics
Tian-Jiao Shao
Summary: We have investigated the effect of field strength on high-order harmonic generation (HHG) in doped systems such as nanosize or bulk materials. Our findings reveal that when the amplitude of the driving laser's vector potential reaches the half-width of the Brillouin zone, the harmonic yield of undoped systems surpasses that of doped systems. This is due to the band-climbing process, which enhances the interband transition of HHG for higher conduction bands. Additionally, the interference between donor-doped states and valence-band states contributes to the HHG.
Article
Multidisciplinary Sciences
Yigeng Peng, Tong Wu, Guanglu Yuan, Lihan Chi, Shicheng Jiang, Konstantin Dorfman, Chao Yu, Ruifeng Lu
Summary: High harmonic generation from solid-state crystals in strong laser fields is understood based on the band structure and periodic boundary conditions. A quasi-band model is developed for a ring-type cluster of cyclo[18]carbon, which predicts solid state-like HHG in this system. Under linearly polarized laser field, cyclo[18]carbon exhibits solid state-like HHG originating from intraband oscillations and interband transitions, providing a potential method to detect molecular or material structures optically. The results are in good agreement with time-dependent density functional theory calculations and contribute to connecting the physics of HHG in gases and solids.
Article
Optics
V. A. Birulia, M. A. Khokhlova, V. V. Strelkov
Summary: This study investigates the attosecond properties of coherent extreme ultraviolet (XUV) generated via high-order frequency mixing (HFM) through theoretical and numerical analysis. The research finds that the duration and carrier-envelope phase of the attosecond pulses generated by HFM can be effectively controlled, especially when one of the generating fields has much lower frequency and intensity compared to the other.
Article
Optics
Gan Wang, Tao-Yuan Du
Summary: The study introduces an imaginary potential to phenomenologically depict the dephasing process in solid HHG, and verifies its validity through comparison with experimental results and SBEs. Diffusion of the quantum wave packet controls the time-frequency characteristic in solid HHG, while the open-trajectory model provides consistent trajectory predictions with quantum simulations.
Article
Nanoscience & Nanotechnology
Christian Heide, Tobias Boolakee, Timo Eckstein, Peter Hommelhoff
Summary: By comparing two experimental schemes for controlling light-field-driven currents in graphene, it was found that two-color control is more efficient than CEP control by over two orders of magnitude. The omega + 2 omega field exhibits significantly more asymmetry in its temporal shape, leading to the superior efficiency of two-color current control. This finding is supported by numerical simulations, suggesting the relevance of these results for fundamental properties of solids at ultrafast timescales and the field of petahertz electronics.
Article
Multidisciplinary Sciences
Zijian Hu, Xiance Xie, Zhihong Yang, Yunhui Wang, Shicheng Jiang
Summary: Solid-state high-order harmonic generation (HHG) is a powerful tool for detecting target properties, but the physical mechanism of HHG in solids is not fully understood. This study reveals the existence of a previously ignored mixture term in solid HHG and compares the orientation-dependent HHG spectra from different mechanisms. The results show similar orientation features for inter-band and mixture HHG, while Berry curvature only produces perpendicularly polarized even harmonics and intra-band perpendicularly polarized even harmonics display special orientation features explained by the orientation-dependent group velocity.
Article
Optics
Thomas Hansen, Simon Vendelbo Bylling Jensen, Lars Bojer Madsen
Summary: Using the Hubbard model, this study investigates the effect of electron-electron correlation on high-order harmonic generation (HHG) in both finite and bulk systems. The results show that finite-size enhancement of the HHG signal is observed, attributed to electrons backscattering off the lattice edges. Furthermore, an enhancement in the high-frequency regime of the HHG spectrum is found with increasing electron-electron correlation.
Article
Optics
Ankur Mandal, Kamal P. Singh
Summary: High harmonic generation (HHG) from atoms near a plasmonic nanostructure interacting with a low intensity driving laser field has the potential to be a table top attosecond pulse source. The carrier envelope phase (CEP) of the driving pulse can efficiently control the harmonic cut-off. Selective enhancements of harmonic spectra due to half-cycle cutoff (HCO) are shown to be highly sensitive to the CEP, in both spatially homogeneous and inhomogeneous driving laser fields. Near cut-off harmonics can be a good candidate for producing isolated attosecond pulses, with control via CEP and the strength of inhomogeneity.
Article
Physics, Multidisciplinary
Long Lin, Tong-Gang Jia, Zhi-Bin Wang, Peng-Cheng Li
Summary: This study theoretically investigates the subcycle spectral structures and dynamics of high-order harmonic generation (HHG) in crystals driven by intense mid-infrared laser pulses. The results reveal a complex time-delay-dependent oscillatory pattern, where the HHG intensity can be enhanced or suppressed by subcycle laser pulses at specific time delays. Analysis of the time-frequency characteristics and probability density distribution of the emitted radiation provides insights into the oscillation structures with respect to the subcycle laser fields.
Article
Optics
Jiayuan Cao, Na Li, Ya Bai, Peng Liu, Ruxin Li
Summary: The study reveals that even-order high harmonics originate from multiple-step transitions among energy bands in momentum space, while odd-order harmonics mainly come from direct transitions. The lower valence band plays a crucial role in generating even harmonics, and the relative intensity of even harmonics increases with the amplitude of the laser field.
CHINESE OPTICS LETTERS
(2021)
Article
Physics, Applied
Cai-Ping Zhang, Ze-Hui Ma, Yu-Zhi Chen, Xiang-Yang Miao
Summary: The high-order harmonic generation from H-2(+) has been investigated using numerical solutions of the two-dimensional time-dependent Schrodinger equation. A pronounced minimum appears in the harmonic spectrum for larger internuclear distance. The competition between electron transition from the ground state to the first excited state and the ionization process at larger internuclear distance is the main cause of the spectral minimum. The electron transition frequency is further demonstrated by superimposing a static electric field and adjusting the orientation angle theta.
MODERN PHYSICS LETTERS B
(2023)
