A5100636589- Laser-Matter Interactions and Applications
- Iron-based superconductors research
- Advanced Fiber Laser Technologies
- Rare-earth and actinide compounds
- Physics of Superconductivity and Magnetism
- Laser Design and Applications
- Spectroscopy and Quantum Chemical Studies
- Laser-Plasma Interactions and Diagnostics
- Mass Spectrometry Techniques and Applications
- Laser-induced spectroscopy and plasma
- Corporate Taxation and Avoidance
- Topological Materials and Phenomena
- Magnetic Properties of Alloys
- Magnetic and transport properties of perovskites and related materials
- Intellectual Capital and Performance Analysis
- Atomic and Molecular Physics
- Advanced Chemical Physics Studies
- Graphene research and applications
- Advanced Condensed Matter Physics
- Solid State Laser Technologies
- Inorganic Chemistry and Materials
- Quantum optics and atomic interactions
- Superconductivity in MgB2 and Alloys
- Electronic and Structural Properties of Oxides
- Spectroscopy and Laser Applications
Jiangsu University
2020
National High Magnetic Field Laboratory
2013-2019
Florida State University
2013-2019
Shanghai Institute of Optics and Fine Mechanics
2009-2017
University of Nebraska–Lincoln
2016
Rutherford Appleton Laboratory
2016
Helmholtz-Zentrum Dresden-Rossendorf
2016
Max Planck Institute of Quantum Optics
2016
Friedrich Schiller University Jena
2016
Chinese Academy of Sciences
2009-2015
The superconductor Sr4V2O6Fe2As2 with transition temperature at 37.2 K has been fabricated. It a layered structure the space group of p4/nmm, and lattice constants = 3.9296Aand c 15.6732A. observed large diamagnetization signal zero-resistance demonstrated bulk superconductivity. broadening resistive was measured under different magnetic fields leading to discovery rather high upper critical field. results also suggest vortex liquid region which reflects anisotropy system. Hall effect...
Remote laser in air based on amplified spontaneous emission (ASE) has produced rather well-collimated coherent beams both backward and forward propagation directions, opening up possibilities for new remote sensing approaches. The ASE-based lasers were shown to enable operation either at ~391 337 nm using molecular nitrogen or ~845 oxygen as gain medium, depending the employed pump lasers. To date, a multi-wavelength that allows dynamically switching operating wavelength not yet been...
Insulators occur in more than one guise, a recent finding was class of topological insulators, which host conducting surface juxtaposed with an insulating bulk. Here we report the observation unusual state electrically bulk that simultaneously yields quantum oscillations characteristics unconventional Fermi liquid. We present oscillation measurements magnetic torque high purity single crystals Kondo insulator SmB6, reveal frequencies characteristic large three-dimensional conduction electron...
We carry out a combined theoretical and experimental investigation on the population distributions in ground excited states of tunnel-ionized nitrogen molecules at various driver wavelengths near- midinfrared range. Our results reveal that efficient couplings (i.e., exchanges) between N_{2}^{+}(X^{2}Σ_{g}^{+}) state N_{2}^{+}(A^{2}Π_{u}) N_{2}^{+}(B^{2}Σ_{u}^{+}) occur strong laser fields. The result inversion near 800 nm, which is verified by our observation amplification seed ∼391 nm....
We experimentally demonstrate the generation of narrow-bandwidth emissions with excellent coherent properties at ∼391 and ∼428 nm from N2+ (B2Σu+ (v' = 0) → X2Σg+ (v 0, 1)) inside a femtosecond filament in air by an orthogonally polarized two-color driver field (i.e. 800 laser pulse its second harmonic). The durations 391 428 are measured to be ∼2.4 ∼7.8 ps, respectively, both which much longer than duration pump harmonic pulses. Furthermore, temporal decay characteristics excited molecular...
A compound with the FeAs-layers, namely, $({\text{Sr}}_{3}{\text{Sc}}_{2}{\text{O}}_{5}){\text{Fe}}_{2}{\text{As}}_{2}$ (abbreviated as FeAs-32522), was successfully fabricated. It has a layered structure space group of $I4/mmm$, and lattice constants $a=4.069\text{ }\text{\AA{}}$ $c=26.876\text{ }\text{\AA{}}$. The in-plane Fe ions construct square which is close to that other FeAs-based superconductors, such REFeAsO ($\text{RE}=\text{rare}$ earth elements)...
By substituting the Fe with $4d$- and $5d$-transition metals Rh, Ir, Pd in ${\text{SrFe}}_{2}{\text{As}}_{2}$, we have successfully synthesized a series of superconductors ${\text{SrFe}}_{2\ensuremath{-}x}{M}_{x}{\text{As}}_{2}$ ($M=\text{Rh}$, Pd) explored phase diagrams them. The systematic evolution lattice constants indicated that part ions were replaced by transition Pd. increasing doping content Pd, antiferromagnetic (AF) state parent is suppressed progressively superconductivity...
When exposed to intense infrared laser pulses of femtosecond duration, molecules such as N${}_{2}$, CO${}_{2}$, and H${}_{2}$O not only become ionized but can also produce lasers a result simultaneous population inversion. Scientists look deep into this ``air lasing'' phenomenon in N${}_{2}$ gas uncover both quantum coherence the rotational wave packets lasing molecular ions its footprint air-laser spectrum.
The symmetry and structure of the superconducting gap in Fe-based superconductors are central issue for understanding these novel materials. So far experimental data theoretical models have been highly controversial. Some experiments favor two or more constant nearly-constant gaps, others indicate strong anisotropy yet suggest zeros ("nodes"). Theoretical also vary, suggesting that absence presence nodes depends quantitatively on model parameters. An opinion has gained substantial currency...
Recently, Yao et al. demonstrated the creation of coherent emissions in nitrogen gas with two-color (800 nm + 400 nm) ultrafast laser pulses [J. Yao, G. Li, C. Jing, B. Zeng, W. Chu, J. Ni, H. Zhang, Xie, Xu, S. L. Chin, Y. Cheng, and Z. New Phys. 15, 023046 (2013)]. Based on this scheme, here we report systematic investigation temporal characteristics radiation emitted at 391 [N${}_{2}{}^{+}$:...
We have successfully synthesized the fluoride-arsenide compounds Ca1−xRExFeAsF (RE=Nd, Pr; x=0,0.6). The X-ray powder diffraction confirmed that main phases of our samples are with ZrCuSiAs structure. By measuring resistivity, superconductivity was observed at 56 K in Nd-doped and 52 Pr-doped x=0.6. Bulk also proved by DC magnetization measurements both samples. Hall effect revealed hole-like charge carriers parent compound CaFeAsF a clear resistivity anomaly below 118 K, while coefficient...
Resistivity, Hall effect and magnetoresistance have been investigated systematically on single crystals of Ba$_{1-x}$K$_x$Fe$_2$As$_2$ ranging from undoped to optimally doped regions. A systematic evolution the quasiparticle scattering has observed. It is found that resistivity in normal state insensitive potassium doping concentration, which very different electron counterpart Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$, where at 300 K reduces half value one when system doped. In stark contrast,...
Recently, amplification of harmonic-seeded radiation generated through femtosecond laser filamentation in air has been observed, giving rise to coherent emissions at wavelengths corresponding transitions between different vibrational levels the electronic B(2)Σ(u)(+) and X(2)Σ(g)(+) states molecular nitrogen ions [Phys. Rev. A. 84, 051802(R) (2011)]. Here, we carry out systematic investigations on its physical mechanism. Our experimental results do not support speculation that such excellent...
Here, we report the discovery of superconductivity in a new transition metal-chalcogenide compound, i.e. Nb2Pd0.81S5, with temperature Tc > 6.6 K. Despite its relatively low Tc, it displays remarkably high and anisotropic superconducting upper critical fields, e.g. mu_0 H_{c2} (T approaching 0 K). 37 T for fields applied along crystallographic b-axis. For field perpendicularly to b-axis, shows linear dependence which coupled temperature-dependent anisotropy suggests that Nb2Pd0.81S5 is...
Electrons in materials with linear dispersion behave as massless Weyl- or Dirac-quasiparticles, and continue to intrigue due their close resemblance elusive ultra-relativistic particles well potential for future electronics. Yet the experimental signatures of Weyl-fermions are often subtle indirect, particular if they coexist conventional, massive quasiparticles. Here we show a pronounced anomaly magnetic torque Weyl semimetal NbAs upon entering quantum limit state high fields. The changes...
Femtosecond laser filament arrays are generated in air by using three kinds of step phase plates with π lag, namely, the semicircular plate (SCPP), quarter-circle (QCPP) and eight-octant (EOPP). Experimental results simulations show that consisting two, four eight filaments, respectively, produced plates. The transverse patterns determined geometrical shapes At same time, separation distances found to vary focal lengths used lenses. We further propose an axicon, array form ring shape could...
We report, for what we believe to be the first time, on generation of remote self-seeding laser amplification by using only one 800 nm Ti:Sapphire femtosecond pulse. The pulse (~ 40 fs) is used generate a filament either in pure nitrogen or ambient air which population inversion between ground and excited states molecular ions realized. Self-induced white light inside then serving as seed amplified. self-induced narrow-band at 428 has duration ~2.6 ps with perfect linear polarization...
We report a structural study of the Weyl semimetals TaAs and TaP, utilizing diffraction imaging techniques, where we show that they contain high density defects, leading to nonstoichiometric single crystals both semimetals. Despite observed defects nonstoichiometry on samples grown using techniques already reported in literature, de Haas--van Alphen measurements TaP reveal quantum oscillations carrier mobility, an indication are quality comparable those elsewhere. Electronic structure...
Large language models (LLMs) have spurred development in multiple industries. However, the growing number of their parameters brings substantial storage and computing burdens, making it essential to explore model compression techniques for parameter reduction easier deployment. We propose SWSC, an LLM method based on concept Shared Weight Similar Channel. It uses K-Means clustering algorithm cluster weights channel-by-channel, generating clusters with highly similar vectors within each. A...
We demonstrate the generation of a coherent x ray in water window region gas cell filled with neon using wavelength-tunable mid-IR femtosecond laser operating at 1 kHz repetition rate. The cutoff energy and conversion efficiency can be optimized by tuning pressure as well focal position.
Measurement of laser intensity inside a femtosecond filament is challenging task. In this work, we suggest simple way to characterize peak the in air. It based on signal ratio measurement two nitrogen fluorescence lines, namely, 391 nm and 337 nm. Because distinct excitation mechanisms, signals lines increase with at different orders nonlinearity. An empirical formula has been deduced according which could be simply determined by ratio.
We demonstrate high-order harmonic generation in a wave form synthesized by multicycle 800-nm chirped laser pulse and chirp-free pulse. Compared with the case of using only pulse, both cutoff extreme ultraviolet supercontinuum can be extended when weak is combined When intensity grows, energy bandwidth grow as well. It found that broad achieved for driving long duration even though reaches 10 optical cycles. An isolated attosecond about 59 obtained, after appropriate phase compensation $11$...
Diatomic molecules (e.g., ${\mathrm{O}}_{2}$) in an intense laser field exhibit a peculiar suppressed ionization behavior compared to their companion atoms. Several physical models have been proposed account for this suppression, while no consensus has achieved. In Letter, we aim clarify the underlying mechanisms behind molecular suppression. Experimental data recorded at midinfrared wavelength and its comparison with that near-infrared revealed intensity dependence of ${\mathrm{O}}_{2}$...