High-energy cutoffs for individual electrons from nonsequential double ionization of helium by a 390 nm laser pulse at intensity $0.8\text{PW}/{\text{cm}}^2$ have been investigated using a classical 3D ensemble. Below the recollision-excitation threshold, both electrons are bound after recollision and get ionized one by one later. With the trajectory back analyzing of electrons with final energies above $2U_p$, we find an additional mechanism for the latter ionized electron after recollision. Both nuclear and laser forces contribute in this mechanism which leads to a broad transverse momentum distribution.

We investigate the topological edge modes in a rhombic waveguide array with imaginary coupling, which is realized by incorporating auxiliary waveguide between the coupled waveguides. By suitably tuning both real and imaginary couplings to generate an effective flux, a non-Hermitian analog of Aharonov-Bohm (AB) cage is formed as the band structures become flat and coalesce into third-order exceptional points (EPs). We show the array can support gapped topological edge modes, which can be explained by mapping the system Hamiltonian into the square root of an anti-parity-time (PT) -symmetric waveguide array. In contrast to the linear power increase of bulk modes, the propagation of edge modes can be conserved or exponentially amplified depending on which termination is initially excited. Our study provides a promising way to realizing robust light propagation.

We propose a method to generate broadband extreme ultraviolet supercontinuum harmonics by using the combination of a phase-stabilized few-cycle laser pulse and a low-frequency field. It is shown that this method can significantly modulate the quantum paths of the harmonics. The harmonic spectrum is extended to $I_p+8.2U_p$ and harmonics with a bandwidth of $4U_p$ become continuous. By adjusting the carrier-envelope phase of the few-cycle pulse, a close-to-Fourier-limit sub-50-as pulse is straightforwardly obtained.

We have investigated the energy correlation of the two electrons from nonsequential double ionization of helium atoms in 800-nm laser fields at intensities below the recollision threshold by quantum calculations. The circular arcs structure of the correlated electron momentum spectra reveals a resonant double-ionization process in which the two electrons transit from doubly excited states into continuum states by simultaneously absorbing and sharing excess energy in integer units of the photon energy. The effectiveness of Coulomb repulsion plays a decisive role in controlling the electronic dynamics in continuum states and is responsible for the dominant back-to-back electron emission and two intensity-independent cutoffs in the two-electron energy spectra.

Infrared and visible image fusion methods based on feature decomposition are able to generate good fused images. However, most of them employ manually designed simple feature fusion strategies in the reconstruction stage, such as addition or concatenation fusion strategies. These strategies do not pay attention to the relative importance between different features and thus may suffer from issues such as low-contrast, blurring results or information loss. To address this problem, we designed an adaptive fusion network to synthesize decoupled common structural features and distinct modal features under an attention-based adaptive fusion (AAF) strategy. The AAF module adaptively computes different weights assigned to different features according to their relative importance. Moreover, the structural features from different sources are also synthesized under the AAF strategy before reconstruction, to provide a more entire structure information. More important features are thus paid more attention to automatically and advantageous information contained in these features manifests itself more reasonably in the final fused images. Experiments on several datasets demonstrated an obvious improvement of image fusion quality using our method.

We theoretically investigate the high-order harmonic generation when the spatially extended systems are irradiated by a two-color laser field. By controlling electron ionization, the $\omega +2\omega$ excitation scheme creates efficient harmonics radiation beyond $I_p+3.17U_p$ with both odd and even harmonics. Calculations show that the harmonics beyond $I_p+3.17U_p$ are well phase locked, moreover, the chirp rate is only 3 as/eV. Using a 5 fs driving pulse, the bandwidth supporting isolated attosecond pulse in harmonic spectrum is 125 eV, and a 68 as single pulse can be obtained straightforwardly.