Comparison of inverse scattering algorithms for designing ultrabroadband fibre Bragg gratings.

We compare different inverse scattering (IS) algorithms used to calculate profiles of fibre Bragg gratings (FBGs) and analyse their robustness, speed and implementation difficulties. We analyse sources of IS algorithm errors and discuss their relative importance. We discuss the optimal choice of IS algorithm for inverse-direct iterative optimisation schemes for grating design. We find that our time-domain layer-peeling method is an order of magnitude faster and more robust than the spectral domain algorithms considered here. We demonstrate that our method is essential to solving highly complex FBG designs demanded by astronomical applications.

A fractal-based fibre for ultra-high throughput optical probes.

A core component of all scanning near-field optical microscopy (SNOM) systems is the optical probe, which has evolved greatly but still represents the limiting component for the system. Here, we introduce a new type of optical probe, based on a Fractal Fibre which is a special class of photonic crystal fibre (PCF), to directly address the issue of increasing the optical throughput in SNOM probes. Optical measurements through the Fractal Fibre probes have shown superior power levels to that of conventional SNOM probes. The results presented in this paper suggest that a novel fibre design is critical in order to maximize the potential of the SNOM.

[The "tourniquet" ischemia-reoxygenation of the extremities as the method of nonmedicinal immunocorrection].

There were adduced the results of studying of cellular and humoral factors of the immunity in a brief-lasting ischemia-reoxygenation of the extremities in 56 patients with surgical diseases and in 31 pupils, in whom the organism reactivity lowering was revealed. It was established, that changes in the ischemia-reoxygenation of the extremities are multifactorial and they are connected primarily with the immunocompetent cells activation. Nonmedicinal method of the "tourniquet" immunocorrection was proposed, which is recommended as a concurrent one - for the recovery acceleration or solely - in the treatment of inflammatory diseases. It may be prescribed as a health-improving method in a rapid fatigue, insomnia, weakness, loss of appetite and other signs of the organism reactivity lowering. Application of the method secures the morbidity lowering in frequently ill pupils.

Solitons and collapse suppression due to parametric interaction in bulk Kerr media.

We demonstrate that weak parametric interaction of a fundamental beam with its harmonic field in a Kerr medium can drastically modify the beam dynamics, giving rise to very complex bifurcation phenomena and quasi solitons. Most importantly, we reveal a novel physical mechanism of the collapse suppression in a bulk optical Kerr medium: parametric coupling to a weakly radiating harmonic field.

Scattering and spiraling of solitons in a bulk quadratic medium.

We analyze the interactions of (2+1) -dimensional parametric solitons and demonstrate nonplanar beam switching in a bulk X((2)) medium, which includes controllable soliton repulsion, spiraling, and fusion. An analytical model predicting the results of the soliton scattering is derived and verified by direct numerics.