S. G. Dinev

Two-wavelength single mode grazing incidence dye laser

Abstract Two-wavelength single mode operation of a N2-laser pumped dye laser is described. The proper choice of a grazing incidence grating and highly selective cavity elements provided a stable operation of the laser. A single mode spectrum of 310 ± 50 MHz is measured and both wavelengths are independently tunable over the entire gain profile of the R6G DN dye.

Interactions of optical vortex solitons superimposed on different background beams

The interaction between two optical vortex solitons (OVS), formed on different background beams is analyzed numerically. Analogous to the one-dimensional case, vector OVS seem obtainable [12]. The relative topological charges of the interacting (off-axis) vortices are found to rule their propagation characteristics. Attraction is found in the case of equal charges, in contrast to the opposite case, where repulsion is present.

Motion control of ensembles of ordered optical vortices generated on finite extent background

Abstract Vortex motion in ordered structures is analysed numerically in the frame of the 2D nonlinear Schrodinger equation. Analogies with superfluid dynamics are presented. It was found that coherent interaction of optical vortex solitons (OVSs) leads to vortex motion, which can be adequately described by the Kelvin law in superfluid dynamics for large offsets between the OVSs. Cancelation of motion in some spatial configurations of vortices and vortex lattices is observed. The possibility to steer the motion of vortex ensembles is discussed.

Experimental demonstration of pulse shaping and shortening by spatial filtering of an induced-phase-modulated probe wave

An asymmetrically induced phase modulation resulting in an intensity-dependent spatial beam deflection and a subsequent spatial filtering have been used for all-optical pulse shaping and shortening. A compression factor of eight and controllable symmetrical super-Gaussian pulses and pulse trains have been observed in a good agreement with previous analyses in a pump-probe beam configuration.

A novel double grazing-incidence single-mode dye laser

Using only one grating and plane parallel glass plate in a novel double-grazing incidence configuration, twice higher dispersion is obtained, resulting in twofold narrowing of the single-pass linewidth, compared to the single grazing-incidence scheme. This laser cavity design features several-times improved signal-to-noise ratio and enhanced stability. Single-mode operation of 210±50 MHz is demonstrated.

Molecular enhanced four-wave parametric generation in sodium atom

A number of resonances have been observed in the excitation spectrum of the uv resonance lines of sodium. The mechanism proposed includes absorption by molecular states, energy transfer to excited atomic levels and four-wave parametric generation enhanced by radiative decay of the excited states.

Influence of nonlinear effects on the statistical properties of a high power density laser beam

Abstract The second-order intensity correlation function g(2)(0) of a laser beam passing through a nonlinear medium has been experimentally found to be a decreasing function of the power density in the medium.

Multiple-charged optical vortex solitons in bulk Kerr media

Abstract We investigate numerically Optical Vortex Solitons (OVSs) with different topological charges ( m ) and show that they are characterised with soliton constants equal to the product of their topological charge and the soliton constant of unit OVS. The propagation characteristics for | m | = 1,2,3 and 4 are investigated. We proposed an approximate analytical description of the field distribution, which was found to be adequate to describe multiple-charged solitons. The instability of these solitons is discussed and they were found to be unstable in the presence of a perturbation.

Parallel guiding of signal beams by a ring dark soliton

Guiding of multiple signal beams in an induced all-optical cable is studied theoretically. A balance relation is derived for the interaction geometry and undistorted propagation of bright elliptical signal beams nested in a single ring dark soliton. The numerical analyses show a remarkable misalignment stability of the parallel guiding scheme.

X-ray emission from a laser irradiated target in the presence of high electric field

Abstract The temporal characteristics of the X-ray emission from a laser irradiated Ai target in a 20 kV/cm electric field are measured with electronic detectors. Spatial and spectral distributions of the X-ray radiation are evaluated using a pinhole camera and filter technique.