Time filter

Source Type

Wang Y.,Huazhong University of Science and Technology | Yang G.,Huazhong University of Science and Technology | Yang G.,MOE Key Laboratory of Fundamental Quantities Measurement | Yang Z.,Huazhong University of Science and Technology | And 9 more authors.
Electrochimica Acta | Year: 2013

Lithium secondary batteries using LiNi0.5Mn1.5O 4 films as a cathode material were prepared by pulsed laser deposition on stainless steel substrates. X-ray diffraction and Field-emission Scanning Electron Microscope results show that the film deposited at 750 C exhibits good crystallinity with well-defined grains structure. Charge/discharge behavior of the batteries under a high cutoff voltage of 4.9 V vs. Li was highly improved by using Li-rich samples, which exhibits larger specific capacity and higher rate capability. Especially, when the substrate temperature increases to 750 C, the reversible capacity maintains 116.8 mAh g-1 after 100 cycles at 0.5C, and the Coulombic efficiency is almost a constant value of 98%. It also exhibits excellent rate capability, as the rates increase to 5 and 10C, and about 95.4% and 92.3% of its initial capacity at 0.2C can be retained. © 2013 Elsevier Ltd. All rights reserved.


Qin M.,Huazhong University of Science and Technology | Zhu X.,Huazhong University of Science and Technology | Zhang Q.,Huazhong University of Science and Technology | Zhang Q.,MOE Key Laboratory of Fundamental Quantities Measurement | And 2 more authors.
Optics Letters | Year: 2012

We theoretically demonstrate a scheme for tomographic reconstruction of asymmetric molecular orbitals based on high-order harmonic generation with a two-color multicycle laser field. It is shown that by adjusting the relative phase of the two fields, the returning electrons can be forced to recollide from one direction for all the orientations of molecules. Thus, the reconstruction of the asymmetric orbitals can be carried out with multicycle laser field. This releases the stringent requirement of a single-cycle pulse with a stabilized and controllable carrier-envelope phase for the tomographic imaging of asymmetric molecular orbitals. © 2012 Optical Society of America.


Hong Z.,Huazhong University of Science and Technology | Zhang Q.,Huazhong University of Science and Technology | Zhang Q.,MOE Key Laboratory of Fundamental Quantities Measurement | Lan P.,Huazhong University of Science and Technology | And 3 more authors.
Optics Express | Year: 2014

A degenerate dual-pump optical parametric chirped-pulse amplifier (OPCPA) for generation of few-cycle intense pulses centered at 1.6 μm is theoretically investigated. By adding the optimized linear chirp to the two pump pulses from Ti:sapphire source and carefully adjusting the delays between the two pumps and seed, the long- and short-wavelength components of the seed pulse are efficiently amplified during the parametric process. Our simulations show that a broadband spectrum spanning from 1.3 μm to 2.1 μm is attained with a conversion efficiency of 22.6%. Signal pulse with a near transform-limited (TL) duration of 10.1 fs can be achieved by simply removing the linear chirp from the output signal. Besides, the compressed signal beam manifests good quality both spectrally and temporally, which allows tightly focusing the signal beam for further use. © 2014 Optical Society of America.


Wang Z.,Huazhong University of Science and Technology | Lan P.,Huazhong University of Science and Technology | Luo J.,Huazhong University of Science and Technology | He L.,Huazhong University of Science and Technology | And 3 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

We theoretically investigate the high-order harmonic generation (HHG) in a two-color multicycle inhomogeneous laser field. The results show that the ionization, acceleration, and recombination of the electrons in the HHG process can be simultaneously controlled with the combination of the temporal waveform synthesis and spatial nonhomogeneity of the laser field. Based on the quantum-mechanical and classical models, the physical mechanism of the supercontinuum generation in such a temporally and spatially shaped field is analyzed and discussed. In contrast to the case of the fundamental field alone, the supercontinuum in the two-color inhomogeneous field shows a constant intensity, a higher yield, and a broader bandwidth, which is beneficial for the efficient generation of broadband-isolated attosecond pulses from multicycle laser fields. © 2013 American Physical Society.


Ding C.,Henan University | Yu R.,Wuhan Institute of Technology | Li J.,Huazhong University of Science and Technology | Li J.,MOE Key Laboratory of Fundamental Quantities Measurement | And 2 more authors.
Journal of Applied Physics | Year: 2014

Unusual dispersion relation of graphene nanoribbons for electrons can lead to an exceptionally strong optical response in the infrared regime and exhibits a very good tunable frequency. According to quantum optics and solid-material scientific principles, here we show the possibility to generate ultraslow infrared bright and dark solitons in graphene under the action of strong magnetic and infrared laser fields. By means of quantum-mechanical density-matrix formalism, we derive the equations of motion that govern the nonlinear evolution of the probe-pulse envelope in this scheme. It is found that, by properly choosing the parameters of the system, the formation and ultraslow propagation of infrared spatial solitons originate from the balance between nonlinear effects and the dispersion properties of the graphene under infrared excitation. Moreover, the unique electronic properties and selection rules near the Dirac point provide more freedom for us to study the linear and nonlinear dynamical responses of the photonics and graphene system. These results may have potential applications in telecommunication and optical information processing. © 2014 AIP Publishing LLC.


Qin M.,Huazhong University of Science and Technology | Qin M.,MOE Key Laboratory of Fundamental Quantities Measurement | Zhu X.,Huazhong University of Science and Technology | Zhu X.,MOE Key Laboratory of Fundamental Quantities Measurement | And 8 more authors.
Optics Express | Year: 2014

We investigate the alignment-dependent high-order harmonic spectrum generated from nonadiabatically aligned molecules around the first half rotational revival. It is found that the evolution of the molecular alignment is encoded in the structural minima. To reveal the relation between the molecular alignment and the structural minimum in the highorder harmonic spectrum, we perform an analysis based on the two-center interferencemodel. Our analysis shows that the structuralminimumposition depends linearly on the inverse of the alignment parameter < cos2q >. This linear relation indicates the possibility of probing the rotational wave-packet dynamics by measuring the spectral minima. © 2014 Optical Society of America.


Hong Z.,Huazhong University of Science and Technology | Zhang Q.,Huazhong University of Science and Technology | Zhang Q.,MOE Key Laboratory of Fundamental Quantities Measurement | Lu P.,Huazhong University of Science and Technology | Lu P.,MOE Key Laboratory of Fundamental Quantities Measurement
Optics Express | Year: 2013

A novel compact dual-crystal optical parametric amplification (DOPA) scheme, collinearly pumped by a Ti:sapphire laser (0.8 μm), is theoretically investigated for efficiently generating broadband IR pulses at non-degenerate wavelengths (1.2 μm∼1.4 μm and 1.8 μm∼2.1 μm). By inserting a pair of barium fluoride (BaF2) wedges between two thin β -barium borate (BBO) crystals, the group velocity mismatch (GVM) between the three interacting pulses can be compensated simultaneously. In this case, the obtained signal spectrum centered at 1.3 μm is nearly 20% broader and the conversion efficiency is increased, but also the pulse contrast and beam quality are improved due to the better temporal overlap. Furthermore, sub-two-cycle idler pulses with carrier-envelope phase (CEP) fluctuation of sub-100-mrad root mean square (RMS) can be generated. Because a tunable few-cycle IR pulse with millijoule energy is attainable in this scheme, it will contribute to ultrafast community and be particularly useful as a driving or controlling field for the generation of ultrafast coherent x-ray supercontinuum. © 2013 Optical Society of America.


Qin M.,Huazhong University of Science and Technology | Zhu X.,Huazhong University of Science and Technology | Liu K.,Huazhong University of Science and Technology | Zhang Q.,Huazhong University of Science and Technology | And 3 more authors.
Optics Express | Year: 2012

The influence of the orbital symmetry on the ellipticity of the high-order harmonics is investigated. It is found that the ellipticity maps have distinct shapes for the molecular orbitals with different symmetry. Our analysis shows that the feature of the harmonic ellipticity map is essentially determined by the nodal structure of the nonsymmetric orbital. The results indicate that the molecular-orbital geometry is imprinted on the ellipticity of the high-order harmonics, which invites the use of ellipticity measurements as a probe of the orbital structure for polar molecules. © 2012 Optical Society of America.


Fan .,Huazhong University of Science and Technology | Wang B.,Huazhong University of Science and Technology | Wang K.,Huazhong University of Science and Technology | Wang K.,MOE Key Laboratory of Fundamental Quantities Measurement | And 4 more authors.
Optics Letters | Year: 2014

We theoretically investigate the plasmonic Talbot effect in monolayer graphene sheet arrays (MGSAs) when surface plasmon polaritons (SPPs) between graphene experience weak coupling. The Talbot effect occurs only when the incident field has a pattern with a few selected periods. The Talbot distance is found to decrease exponentially with the decreasing period of the MGSA and can be as small as 1/20 of the incident wavelength. In addition, the Talbot distance can be further reduced by increasing the chemical potential of graphene or operating at longer wavelengths. © 2014 Optical Society of America.


Ma J.,Huazhong University of Science and Technology | You C.,Huazhong University of Science and Technology | Si L.-G.,Huazhong University of Science and Technology | Xiong H.,Huazhong University of Science and Technology | And 4 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We propose a scheme to efficiently manipulate optomechanical systems into and out of chaotic regimes. Here the optical system is coherently driven by a continuous-wave bichromatic laser field consisting of a pump field and a probe field, where the beat frequency of the bichromatic components plays an important role in controlling the appearance of chaotic motion and the corresponding chaotic dynamics. With state-of-the-art experimental parameters, we find that a broad chaos-absent window with sharp edges can be formed by properly adjusting the powers of the bichromatic input field. Moreover, the lifetime of the transient chaos and the chaotic degree of the optomechanical system can be well tuned simply by changing the initial phases of the bichromatic input field. This investigation may be useful for harnessing the optomechanical nonlinearity to manipulate rich chaotic dynamics and find applications in chaos-based communication. © 2014 American Physical Society.

Loading MOE Key Laboratory of Fundamental Quantities Measurement collaborators
Loading MOE Key Laboratory of Fundamental Quantities Measurement collaborators