A5016773116- Laser-Matter Interactions and Applications
- Terahertz technology and applications
- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Spectroscopy and Laser Applications
- Advanced Fiber Laser Technologies
- Mass Spectrometry Techniques and Applications
- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Laser Design and Applications
- Quantum optics and atomic interactions
- High-pressure geophysics and materials
- Photonic and Optical Devices
- Quantum, superfluid, helium dynamics
- Laser-Plasma Interactions and Diagnostics
- Gyrotron and Vacuum Electronics Research
- Metamaterials and Metasurfaces Applications
- Semiconductor Quantum Structures and Devices
- Ion-surface interactions and analysis
- Mechanical and Optical Resonators
- Atomic and Subatomic Physics Research
- Diamond and Carbon-based Materials Research
- Plasmonic and Surface Plasmon Research
- Superconducting and THz Device Technology
- Spectroscopy Techniques in Biomedical and Chemical Research
National University of Defense Technology
2016-2025
Northwest Normal University
2018
University of Ottawa
2006-2007
Shanghai University
2006
Kansas State University
2000-2005
China Institute of Atomic Energy
1990
University of Cologne
1988
We have extended the tunneling ionization model of Ammosov-Delone-Krainov (ADK) for atoms to diatomic molecules by considering symmetry property and asymptotic behavior molecular electronic wave function. The structure parameters several needed calculating rates using this ADK been obtained. theory is applied calculate ratios signals with their companion that nearly identical binding energies. origin suppression some has identified. predicted pairs $({\mathrm{D}}_{2}:\mathrm{Ar},$...
It was recently shown that the highest molecular orbital of N2 could be reconstructed from a series high harmonic measurements. Existing theories generation and tomographic imaging are based on single active electron approximation ignores essential quantum mechanical properties such as indistinguishability identical particles Pauli exclusion principle. We show that, when fully antisymmetrized multielectron wave functions electronic relaxation in cation considered, tomography records image...
Supercontinuum (SC) light sources hold versatile applications in many fields ranging from imaging microscopic structural dynamics to achieving frequency comb metrology. Although such broadband are readily accessible the visible and near infrared regime, ultraviolet (UV) extension of SC spectrum is still challenging. Here, we demonstrate that joint contribution strong field ionization quantum resonance leads unexpected UV continuum radiation spanning 100 nm bandwidth molecular nitrogen ions....
The orientation-dependent strong-field ionization of CO molecules is investigated using the fully propagated three-dimensional time-dependent Hartree-Fock theory. full results are in good agreement with recent experiments. comparisons between method and single active orbital show that although core electrons generally more tightly bound contribute little to total yields, their dynamics cannot be ignored, which effectively modifies behavior highest occupied molecular orbital. By incorporating...
We perform a joint measurement of terahertz waves and high-harmonics generated from argon atoms driven by fundamental laser pulse its second harmonic. By correlating their dependence on the phase delay between two pulses, we determine generation THz in tens attoseconds precision. Compared with simulations models, find that laser-assisted soft collision electron wave packet atomic core plays key role. It is demonstrated rescattering process, being indispensable high-harmonic processes,...
Terahertz radiation from tunneling ionization of gaseous atoms and molecules in the two-color laser fields with various polarizations has been investigated. We experimentally demonstrate that efficiency terahertz emission circularly polarized same helicity is 5 times higher than linearly femtosecond pulses high intensity. By solving time-dependent Schrödinger equation, this enhancement well explained based on analysis electron subsequent dynamics.
Isolated attosecond pulses with a duration of 88 as are generated in the spectral range 29–72 eV using double optical gating technique. The gate width is set to be shorter than half cycle avoid carrier envelop phase stabilization 4.2 fs driving laser centered at 800 nm. pulse measured technique frequency resolved for complete reconstruction bursts.
Understanding the evolution of molecular electronic structures is key to explore and control photochemical reactions photobiological processes. Subjected strong laser fields, holes are formed upon ionization evolve in attosecond timescale. It crucial probe dynamics real time with attosecond-temporal atomic-spatial precision. Here, we present interferometry that enables situ manipulation carbon dioxide molecules via phase-locked electrons (propagating opposite directions) a laser-triggered...
We report the laser-chirp controlled terahertz (THz) wave generation from two-color-laser-induced air plasma. Our experimental results reveal that THz is affected by both laser energy and chirp, leading to radiation minima can be quantitatively reconstructed using linear-dipole-array model. The phase difference between two colors, determined chirp intensity of laser, account for minima. Furthermore, we observe an asynchronous variation in generated spectrum, which suggests a...
The strong field approximation is used to investigate the harmonic generation of aligned ${\mathrm{N}}_{2}$ and ${\mathrm{O}}_{2}$ molecules. It shown that angular dependence yields high-order from molecules are different, which can be attributed orbital symmetry outmost electrons. theory applied study recent pump-probe experiments where pump pulse was produce time-dependent partial alignment probe generate harmonics. Good agreement with found.
It is shown that the alignment dependence of yields high-order harmonic generation (HHG) from molecules by intense lasers governed orbital symmetry outermost electron(s). For ${\mathrm{N}}_{2}$, with its ${\ensuremath{\sigma}}_{g}$ electron, HHG yield maximal when are aligned laser polarization direction, in agreement recent experiment Itatani et al. [Nature 432, 867 (2004)]. ${\mathrm{O}}_{2}$, ${\ensuremath{\pi}}_{g}$ peaks at about 45\ifmmode^\circ\else\textdegree\fi{} axis. We emphasize...
High harmonic radiation is produced when atoms or molecules are ionized by an intense femtosecond laser pulse. The radiated spectrum has been shown experimentally to contain information on the electronic structure of molecule, which can be interpreted as image a single molecular orbital. Previous theory for high generation limited single-active-electron approximation. Utilizing semisudden approximation, authors develop recombination step in and tomographic reconstruction multielectron...
We present an efficient method to generate a ultrashort attosecond (as) pulse when model ${\text{He}}^{+}$ ion is exposed the combination of intense few-cycle chirped laser and its 27th harmonics. By solving time-dependent Schr\"odinger equation, we found that high-order harmonic generation (HHG) from enhanced by seven orders magnitude due presence pulse. After optimizing chirp fundamental pulse, show cut-off energy generated harmonics extended effectively ${I}_{p}+25.5{U}_{p}$. As result,...
Abstract Ultrafast ionization of atoms or molecules by intense laser pulses creates extremely non-stationary ionic states. This process triggers attosecond correlated electron-hole dynamics and subsequent ultrafast non-equilibrium evolution matters. Here we investigate the interwoven dynamic evolutions neutral nitrogen together with ions created through transient tunnel in an field. Based on proposed theoretical frame, it is found that molecular are primarily populated electronically excited...
Abstract Strong field ionization injects a transient vacancy in the atom which is entangled to outgoing photoelectron. When electron finally detached, ion populated at different excited states with part of coherence information lost. The preserved matter after interacting intense short pulses has important consequences on subsequent nonequilibrium evolution and energy relaxation. Here we employ attosecond absorption spectroscopy measure time-delay resonant transitions krypton during their...
Attosecond transient absorption spectroscopy (ATAS) is becoming an indispensable and powerful tool in the emerging field of attochemistry, while interpretation measurements often requires full considerations coupling among various freedoms motion. Here we develop ionization-coupling model to incorporate explore coupled electronic-vibrational dynamics nitrogen ions induced by strong-field ionization. It found coherent vibrational wave packet on involved electronic state created with a broad...
Abstract This paper provides an overview of the current status ultrafast and ultra-intense lasers with peak powers exceeding 100 TW examines research activities in high-energy-density physics within China. Currently, 10 high-intensity over are operational, about additional being constructed at various institutes universities. These facilities operate either independently or combined one another, thereby offering substantial support for both Chinese international development efforts physics.
We demonstrate the possibility of determining dependence ionization probabilities on alignment molecules in a double-pulse laser experiment. A short pump pulse is used to generate rotational wave packet which produces aligned during periods revival. The by subsequent probe vs time delay are calculated for ${\mathrm{O}}_{2}$ and ${\mathrm{N}}_{2}$ at different temperatures. Distinct predicted, results interpreted terms geometry charge distributions valence electrons two molecules.
The kinetic energy distribution of D+ ions resulting from the interaction a femtosecond laser pulse with D2 molecules is calculated based on rescattering model. From analyzing molecular dynamics, it shown that recollision time between ionized electron and D+2 ion can be read peaks to attosecond accuracy. We further suggest more precise reading clock achieved by using shorter fs pulses (about 15 fs).
We studied the angular distributions of fragmented ions diatomic molecules in an intense linearly polarized short laser pulse. In addition to well-known dynamic alignment neutral before ionization, we identified a more important post ionization effect molecular ions. The latter is modelled quantum mechanically as resulting from breakup rotating linear rotor. showed that only for very pulses are two mechanisms not important. this case mimic shape electronic density outermost orbital.
Theoretical and computational modeling of nonequilibrium processes in warm dense matter represents a significant challenge. The electron-ion relaxation process hydrogen is investigated here by molecular dynamics using the constrained electron force field (CEFF) method. CEFF evolves wave packets that incorporate dynamic quantum diffraction obviates Coulomb catastrophe. Predictions from this model reveal temperature times as much three longer than prior results based on statistical potentials....
We propose a novel approach based on the subcycle injection of carriers to extend high-energy cutoff in solid-state high harmonics. The mechanism is first examined by employing standard single-cell semiconductor Bloch equation (SC SBE) method for one-dimensional (1D) Mathieu potential model ZnO subjected intense linearly polarized midinfrared laser field and extreme-ultraviolet pulse. Then, we use coupled solution Maxwell propagation SC SBE propagate fundamental through sample, find that...
We present a quantum theory of the decay an autoionizing state created in attosecond xuv (extreme ultraviolet) pump and laser probe measurements within strong field approximation employing resonance parameters from Fano's theory. From electron spectra versus pump-probe time delay, we show how lifetimes resonances can be extracted directly domain measurements.
We study the generation of terahertz radiation from atoms and molecules driven by an ultrashort fundamental laser its second-harmonic field solving time-dependent Schr\"odinger equation (TDSE). The comparisons between one-, two-, three-dimensional TDSE numerical simulations show that initial ionized wave packet subsequent acceleration in rescattering with long-range Coulomb potential play key roles. also present dependence optimum phase delay yield on intensity, wavelength, duration, ratio...