98 research outputs found
Efficient generation of isolated attosecond pulses with high beam-quality by two-color Bessel-Gauss beams
The generation of isolated attosecond pulses with high efficiency and high
beam quality is essential for attosec- ond spectroscopy. We numerically
investigate the supercontinuum generation in a neutral rare-gas medium driven
by a two-color Bessel-Gauss beam. The results show that an efficient smooth
supercontinuum in the plateau is obtained after propagation, and the spatial
profile of the generated attosecond pulse is Gaussian-like with the divergence
angle of 0.1 degree in the far field. This bright source with high beam quality
is beneficial for detecting and controlling the microscopic processes on
attosecond time scale.Comment: 3 pages, 3 figure
Enhanced mechanical, thermal and flame retardant properties by combining graphene nanosheets and metal hydroxide nanorods for Acrylonitrile–Butadiene–Styrene copolymer composite
Three metal hydroxide nanorods (MHR) with uniform diameters were synthesized, and then combined with graphene nanosheets (GNS) to prepare acrylonitrile–butadiene–styrene (ABS) copolymer composites. An excellent dispersion of exfoliated two-dimensional (2-D) GNS and 1-D MHR in the ABS matrix was achieved. The effects of combined GNS and MHR on the mechanical, thermal and flame retardant properties of the ABS composites were investigated. With the addition of 2 wt% GNS and 4 wt% Co(OH)2, the tensile strength, bending strength and storage modulus of the ABS composites were increased by 45.1%, 40.5% and 42.3% respectively. The ABS/GNS/Co(OH)2 ternary composite shows the lowest maximum weight loss rate and highest residue yield. Noticeable reduction in the flammability was achieved with the addition of GNS and Co(OH)2, due to the formation of more continuous and compact charred layers that retarded the mass and heat transfer between the flame and the polymer matrix
Wavelength dependence of electron localization in the laser-driven dissociation of H
We theoretically investigate the laser wavelength dependence of asymmetric
dissociation of H. It is found that the electron localization in
molecular dissociation is significantly manipulated by varying the wavelength
of the driving field. Through creating a strong nuclear vibration in the
laser-molecular interaction, our simulations demonstrate that the few-cycle
mid-infrared pulse can effectively localize the electron at one of the
dissociating nuclei with weak ionization. Moreover, we show that the observed
phase-shift of the dissociation asymmetry is attributed to the different
population transfers by the remaining fields after the internuclear distances
reach the one-photon coupling point.Comment: 11 pages, 7 figure
Laser-polarization-dependent photoelectron angular distributions from polar molecules
Photoelectron angular distributions (PADs) of oriented polar molecules in
response to different polarized lasers are systematically investigated. It is
found that the PADs of polar CO molecules show three distinct styles excited by
linearly, elliptically and circularly polarized lasers respectively. In the
case of elliptical polarization, a deep suppression is observed along the major
axis and the distribution concentrates approximately along the minor axis.
Additionally, it is also found that the concentrated distributions rotate
clockwise as the ellipticity increases. Our investigation presents a method to
manipulate the motion and angular distribution of photoelectrons by varying the
polarization of the exciting pulses, and also implies the possibility to
control the processes in laser-molecule interactions in future work.Comment: 12 pages and 7 figure
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