Time-resolved dynamics of two-dimensional transverse patterns in broad area lasers

Synthetic gauge fields for light beams in optical resonators

A method to realize artificial magnetic fields for light waves trapped in passive optical cavities with anamorphic optical elements is theoretically proposed. In particular, when a homogeneous magnetic field is realized, a highly degenerate Landau-level structure for the frequency spectrum of the transverse resonator modes is obtained, corresponding to a cyclotron motion of the optical-cavity field. This can be probed by transient excitation of the passive optical resonator.

Formation of spiral patterns in dielectric-barrier discharge investigated by an intensified-charge coupled device

The formation of the spiral patterns in dielectric-barrier discharge is investigated through instantaneous pictures at successive driving half cycles taken by an intensified-charge coupled device (ICCD). The filaments discretely distributed in each instantaneous picture corresponding to one discharge pulse indicate that they are the basic unit of the spiral patterns. An individual filament can undergo two movement states within continuous discharges: pinning at the same locations and shifting along the arm with a small displacement (less than the filament radius), which results in the formation of smooth arms. The averaged correlation time between the instantaneous patterns is found to be about two driving half-cycles by the cross-correlation calculations.

Wave pattern and weak localization of chaotic versus scarred modes in stadium-shaped surface-emitting lasers

We explore the lasing mode selection between the chaotic and scarred modes in stadium-shaped vertical-cavity surface-emitting lasers (VCSELs). Experimental results reveal that the spatial gain distribution in the active layer of a VCSEL can be modified via the aperture size to favor the generation of either the chaotic or the scarred modes. Experimentally obtained chaotic and scarred modes are further employed to perform statistical analysis of wave function intensities for making a comparison with predictions based on the nonlinear σ model. We verify that the scarring effect can be quantitatively relevant to the weak-localization correction in the intensity probability distribution.

Three-dimensional coherent optical waves localized on trochoidal parametric surfaces

We theoretically demonstrate that the three-dimensional (3D) coherent laser waves formed by the degenerate Laguerre-Gaussian modes with different longitudinal indices are well localized on rotating trochoidal parametric surfaces. We further use a large-Fresnel-number laser system to realize the existence of the laser modes related to trochoidal coherent states. Experimental results reveal that the exotic laser modes generally originate from a superposition of two degenerate standing-wave trochoidal coherent states.

Evolution of the correlation between orthogonal polarization patterns in broad-area lasers

We measure polarization-resolved instantaneous patterns in a large-aspect ratio quasi-isotropic Nd:YAG laser. High correlation between the instantaneous orthogonal polarization patterns recorded at the earlier stages of the laser pulse has been found due to the strong cross saturation between both polarization modes.

Dynamic transition from modelike patterns to turbulentlike patterns in a broad-area Nd:YAG laser

We report the first experimental observation to our knowledge of a dynamic transition from modelike patterns to completely disordered patterns in a large-aspect-ratio Nd:YAG laser. Recordings of near-field patterns with an integration time as small as 1 ns allow us to follow the evolution of the transverse intensity profile along the output pulse of the laser.