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The evolution properties and the spectral degree of coherence of a partially coherent multi-Gaussian Schell-model vortex (MGSMv) beam propagating in uniaxial crystals orthogonal to the optical axis are studied. Propagation expression for the cross-spectral density and the average intensity of the partially coherent MGSMv beam propagating in uniaxial crystals are derived. Some analyses are illustrated by numerical examples related to the propagation properties and coherence vortices of the partially coherent MGSMv beam in uniaxial crystals. Numerical results show that, upon propagating in uniaxial crystals, the partially coherent MGSMv beam loses its initial dark center distribution. After propagating for sufficient distances, the partially coherent MGSMv beam will also evolve into a flat-topped beam. The evolution behavior of average intensity and coherent vortices depends on the crystal including the ratio of extraordinary and ordinary refractive indices, and beam parameters including the spatial correlation length and topological charge of the beams, as well as the propagation distance. [ABSTRACT FROM AUTHOR]

A diode-end-pumped quasi-three-level orthogonally polarized continuous-wave dual-wavelength Nd:YVO4 laser was demonstrated. We analyze the condition of gain-to-loss balance via an uncoated glass plane to achieve the simultaneous dual-wavelength operation. We experimentally demonstrate the orthogonally polarized dual-wavelength laser with a Nd:YVO4 crystal. The simultaneous dual-wavelength Nd:YVO4 laser at 914 nm in π-polarization and 915 nm in σ-polarization is realized. At an incident pump power of 12 W, the output power obtained at 914 and 915 nm is 1.19 and 0.86 W, respectively. To the best of our knowledge, this is the first work realizing quasi-three-level orthogonally polarized dual-wavelength operation in Nd-doped lasers. [ABSTRACT FROM PUBLISHER]

The analytical expressions for the cross-spectral density, average intensity and beam propagation factors of a rectangular Laguerre–Gaussian correlated Schell-model (RLGCSM) beam propagating through isotropic non-Kolmogorov turbulence are derived. The influence of the beam and turbulence parameters on the RLGCSM beam is numerically calculated. It is shown that the evolution behavior of the average intensity depends on the beam parameters including the coherence width, beam order, as well as the propagation distance. The RLGCSM beam propagating in turbulence will exhibit self-splitting and self-combining properties, splitting into (m + 1) × (n + 1) beam spots and combining into a Gaussian beam during propagation. The RLGCSM beam has advantages over the Gaussian Schell-model beam or Gaussian beam in turbulence for reducing turbulence-induced degradation. [ABSTRACT FROM AUTHOR]

In this paper, a flat-topped vortex hollow beam, which is a new mathematical model for dark hollow beams, has been introduced. The propagation properties of a flat-topped vortex hollow beam of circular and elliptical symmetry are investigated. According to the Collins formula under paraxial conditions, analytical formulas of the average intensity and the effective beam radius of a flat-topped vortex hollow beam are derived. Compared with a general flat-topped hollow beam by using numerical simulation, the propagation characteristics of a flat-topped vortex hollow beam are studied in detail. The relationships between the effective beam radius and propagation distance z are also provided graphically. From the graphical outputs of the receiver plane, it is observed that a flat-topped vortex hollow beam propagating to the far field still maintains a dark hollow spot and the radius of the dark hollow spot will get gradually larger as the propagation distance is extended. Furthermore, the flat-topped vortex hollow beam carrying the orbital angular momentum can be widely applied in atomic optics. [ABSTRACT FROM AUTHOR]