We address the stability of light bullets supported by Bessel optical lattices with out-of-phase modulation of the linear and nonlinear refractive indices. We show that spatial modulation of the nonlinearity significantly modifies the shapes and stability domains of the light bullets. The addressed bullets can be stable, provided that the peak intensity does not exceed a critical value. We show...

An expression for the bit error rate of a multiple subcarrier intensity-modulated atmospheric optical communication system employing spatial diversity is derived. Spatial diversity is used to mitigate scintillation caused by atmospheric turbulence, which is assumed to obey lognormal distribution. Optimal but complex maximum ratio, equal gain combining (EGC) and relatively simple selection combi...

transfer matrix method (tmm) has been applied to analyze characteristics of semiconductor laser optical amplifiers. the input signal is sinusoidal modulating wave and we do not assume the modulating bias signal as well. we have shown that the distoration arises from gain modulation at low modulation frequencies, but in microwave modulation frequencies, the gain takes an average value and the re...

We apply the polar decomposition of the Mueller matrix describing a liquid-crystal-on-silicon display to identify the diattenuator, depolarizer, and retarder contributions as a function of the gray level. The retarder contribution is expressed in terms of the equivalent Jones matrix to apply previous techniques to evaluate the phase modulation. This allows searching for optimized polarization c...

We have fabricated flip-chip-bondable vertical-cavity surface-emitting lasers (VCSELs) emitting at 894.6 nm wavelength for Cs-based atomic clock applications. For polarization control, we have integrated shallow semiconducting surface gratings in the top Bragg mirror. A modulation bandwidth of more than 5GHz is reached at only 0.5mA bias. Modulation current efficiency factors larger than 12GHz/...

We studied the influence of steady annular light on the kinetics and sensitivity of horizontal cell (HC) responses to modulation of the intensity of small concentric spots in the turtle retina. As shown by previous investigators, when the intensity of the annulus was equal to the mean spot intensity, spot response kinetics were the same as those for the modulation of spatially uniform light. Tu...

In a radiotherapy department having more than one linear accelerator, it is rather common to match the dose output of all machines. In particular, the recently developed flattening filter free mode requires new investigations regarding the feasibility of matching and the consequences for quality assurance and workload. This refers also to the beam model of the radiotherapy treatment planning sy...

We study the phase behaviour of a two-dimensionally confined hard sphere colloidal system in the presence of a periodic light field of two interfering laser beams using Monte Carlo simulations. For a given packing fraction of the particles, the colloidal system undergoes a transition from a modulated liquid to a modulated crystal as the light intensity is increased, corresponding to laser induc...

the determination of the optimal distribution of the catalytic activity profile, whichmaximizes the catalytic effectiveness, in created unsteady state conditions, is analyzed andtreated numerically for the case of a simple reaction. it was proven that the modulation, of thetemperature and the reactant concentration of the external bulk fluid, leads to a considerableincrease of the catalytic eff...