Double-slit interference of a relativistic vortex laser

The interference of a relativistic vortex laser is investigated for the case when a linearly polarized Laguerre–Gaussian pulse impinges on a double-slit solid target. Three-dimensional particle-in-cell simulation results show that the interference fringes of high-order harmonics are twisted, similar to that of the fundamental vortex laser. The twisting order of the interference pattern is determined by the order of the vortex high-order harmonics, which can be explained by the classic double-slit interference models. The usual double-slit interference has been extended to the regime of relativistic intensity,which may have potential applications for measuring the topological charge of vortex high-order harmonics.

Effects of Spontaneously Generated Coherence on Intensity-Intensity Correlation in a Driven Y-Type Atom

In this paper,we investigate the spontaneously generated coherence(SGC) effects on the fluorescence fields intensity-intensity correlation in a resonant driven four-level Y-type atomic system.By using a strong control field, in the absense of SGC effects,strong correlation and anticorrelation fluorescence photons can be produced from two ladder transitions in this system respectively.However,in the presence of SGC effects,the fluorescence fields correlation properties are reversed for the two transitions.The above phenomena can be traced to the quantum destructive or constructive interference in terms of dressed states.

Self-organized voids revisited:Experimental verification of the formation mechanism

We conduct several experiments to further clarify the formation mechanism of a self-organized void array induced by a single laser beam, including energy-related experiments, refractive-index-contrast-related experiments, depth-related experiments, and effective-numerical-aperture experiment. These experiments indicate that the interface spherical aberration is indeed responsible for the formation of void arrays.

SUPPRESSION OF SIDELOBES IN SINGLE-PHOTON 4PI CONFOCAL MICROSCOPY BY FORSTER RESONANT ENERGY TRANSFER

Recently,we theoretically demonstrate that utilization of silica nanobeads co-doped with Cy3 and Cy5 molecules instead of single dye molecules asfluorescent labels can enable optical resolutions far beyond the diffraction-limit.Here,we show that by combining the 4Pi microscopy and the novelfluorescent label,it is possible to completely suppress the sidelobes in 4Pi focal spot and significantly enhance the optical resolution in the axial direction.

Detecting benign uterine tumors by autofuorescence lifetime imaging microscopy through adjacent healthy cervical tissues

The endogenous fluorophores such as reduced nicotinarmide adenine dinucleotide(phosphate)(NAD(P)H)and favin adenine dinucleotide(FAD)in cells and tissues can be imaged by fuo-rescence lifetime imaging microscopy(FLIM)to show the tisute morphology features,as well as the biomolecular changes in microenvironment.The two important coenzymes in cellular metabolism,NAD(P)H and FAD,can be used to monitor the cellular metabolic status.This work proposed a novel method to study the uterine metabolism at the adjacent site of healthy cervix.It was found that the benign uterine tumors such as leiomyomas and adenomyosis with abnormal cell growth can be detected by measuring the fluorescence lifetime of NAD(P)H and FAD in adjacent healthy cervical tisues.This method opened a novel strategy for alicted women to undergo the cervical biopsies instead of hysterectomies for detecting tumors,which can preserve the fertility of patients.The FLIM studying on NAD(P)H and FAD indicated the correlation between metabolism and some diseases,including diabetes,hyperthyroidism and obesity.It was also suggested that the metabolic level might be quite different for a patient with a malignant tumnor history.

Mode-locked fiber laser with MoSe_2 saturable absorber based on evanescent field

An all-fiber mode-locked fiber laser was achieved with a saturable absorber based on a tapered fiber deposited with layered molybdenum selenide(MoSe_2). The laser was operated at a central wavelength of 1558.35 nm with an output spectral width of 2.9 nm, and a pulse repetition rate of 16.33 MHz. To the best of our knowledge, this is the first report on mode-locked fiber lasers using MoSe_2 saturable absorbers based on tapered fibers.

Pulse compression and supercontinuum at different powers of femtosecond pulses in water

Propagation of femtosecond light pulses in water is investigated.By changing input power from slightly above to highly above threshold for self-focusing,it is shown that either group velocity dispersion(GVD) or multi-photon ionization(MPI)and multi-photon absorption(MPA)may arrest the collapse.When MPI and MPA dominate the propagation,the pulse can be self-compressed to a few optical cycles.In spectral domain,MPI alone induces a strong blue shift.MPA can restrain this strong blue shift.

Size dependence of the maximum energy of protons from Coulomb explosion of methane clusters under intense femtosecond laser irradiation

An investigation of the cluster size dependence of the maximum energy of protons ejected from explosion of methane clusters in an intense femtosecond laser field has been conducted on the basis of the cluster size estimation by Rayleigh scattering measurements. The interaction of a 2×1016-W/cm2 intense laser pulse (790 nm, 60 fs) with the methane clusters revealed that the clusters were Coulomb exploded and the maximum energy (Emax) of the protons produced was linearly proportional to the square of the cluster radius (rc2). In a cluster size range, with the methane cluster radii up to about 3 nm, the established relation of Emax and rc2 was found to be Emax(keV)=3.3 + 0.75rc2(nm2), in good agreement with the simulation results. This demonstrated that Coulomb explosion of ionic clusters (C+4H4+)n took place following the cluster vertical ionization in the laser-cluster interaction.

Diode-pumped efficient laser action of Yb^(3+):LYSO crystal

Effective diode-pumped continuous wave (CW) tunable laser action of a new alloyed crystal Yb:LYSO is demonstrated. The alloyed LYSO crystal possesses the desirable physical and laser performance of La2SiO5 (LSO), as well as the favorable growth properties and costs of Y2SiO5 (YSO) in the same time. With a 5 at.-% Yb:LYSO sample, the output power of 2.84 W at 1085 nm and an optical-to-optical conversion efficiency of 54.5% are achieved. Its laser wavelength can be tuned over a broad range of 81 nm, from 1030 to 1111 nm.

Effect of vacuum-induced coherence on lasing without inversion in an equispaced three-level ladder system

The effects of vacuum-induced coherence (VIC) on the properties of the absorption and gain of the probe field in an equispaced three-level ladder atomic system are investigated. It is found that lasing without inversion (LWI) is remarkably enhanced due to the effect of VIC in the case of the small incoherent pump rate.

Influence of atomic densities on propagation property for ultrashort pulses in a two-level medium

The influence of atomic densities on the propagation property for ultrashort pulses in a two-level atom (TLA) medium is investigated. With higher atomic densities, the self-induced transparency (SIT) cannot be recovered even for 2π ultrashort pulses. New features such as pulse splitting, red-shift and blue-shift of the corresponding spectra arise, and the component of central frequency gradually disappears.

A novel type of solitons in electron-ion plasmas

By using one-dimensional self-consistent relativistic fluid model, a novel type of moving relativistic electromagnetic solitons with high intensity in electron-ion plasmas where the ion dynamics is taken into account is investigated numerically. Unlike solitons with single-humped scalar potential found in previous studies, these solitons possess multi-humped scalar and vector potential. The existence of such soliton solutions is investigated in plasmas with different background densities, and the properties of these solitons are presented in detail. We found that the peculiar profile of electron density has alternating regions of humps and dips like a Bragg's grating.

Entanglement dynamics of non-interacting two-qubit system under a squeezed vacuum environment

Entanglement dynamics of two non-interacting atoms in a squeezed vacuum reservoir is studied.Several examples with different initial entangled states are investigated,and it is found that entangled atoms become disentangled faster in squeezed vacuum than in ordinary vacuum,and larger squeezing results in faster entanglement decay.The time evolution of the concurrence and the separability'distance'A can be used to explain this novel entanglement sudden death phenomenon.

Electron acceleration in a tightly focused laser beam

Electron acceleration in a tightly focused ultra-intensity linear polarized laser beam is investigated numerically. It has been found that the acceleration is strong phase dependent and is periodic to the variety of the initial laser field phase. When optimal initial parameters are chosen, the electron can be accelerated effectively. The accelerated electrons are emitted in pulses of which the full width is less than the half period of the laser field.