Interaction and fusion of light pulses at the dynamical four-wave mixing in photorefractive media
All-optical control of impulse parameters is realized via a dynamical transmission four-wave mixing. We show that the nonlinear system, which includes both coupled wave equations and an evolution equation for the dynamical grating amplitude, contains soliton-like solution for the intensity pattern formed in the medium. The nonlocality of the nonlinear response is the main important requirement to the soliton-like solution is established during the wave-mixing process. On some determined conditions the convergence of input pulses into one pulse takes place (i.e. the merge of the solitons) that lead to the dramatic changes of the output pulse shapes and intensities. The precise conditions, when the impulse output can be driven by another guiding pulse are obtained and discussed.
Soliton Profile of the Dynamic Grating Amplitude and its Alteration by Photorefractive Wave Mixing
The wave-mixing problem is considered with respect to the amplitude of the dynamic grating forming in photorefractive crystals. For non-local response and transmission geometry the grating amplitude dynamics is described by a sine-Gordon equation. Hence the grating amplitude has a soliton form. For an experimental verification the spatial distribution of the grating amplitude was imaged within a LiNbO3 sample by a topographic set-up. The results on changes of the profile of the grating amplitude versus input intensity ratio were in good qualitative agreement with the theoretical prediction. Such alterations of the grating amplitude profile can possibly be applied to signal processing.
In-House Industrial Production of the Superconducting Conductor for the 43 T Hybrid Magnet of LNCMI-Grenoble
The hybrid magnet being built at LNCMI-Grenoble is based on the combination of resistive inserts, made up of Bitter and polyhelix coils, with a large bore superconducting outsert. It will produce, in the first step, an overall continuous magnetic field of 43 T in a 34 mm warm bore aperture. The superconducting coil will provide a nominal magnetic field of 8.5 T in a 1.1 m cold bore diameter. It relies on the novel development of an Nb-Ti/Cu Rutherford Cable On Conduit Conductor (RCOCC) cooled down to 1.8 K by a bath of superfluid helium pressurized at 1200 mbar. After a brief reminder of the specificity of hybrid magnets, namely the strong electromechanical coupling between resistive and superconducting coils, the main requirements of the RCOCC for efficient and reliable magnet operation are given. The test and validation phases prior to the industrial production of the RCOCC are reported, including the trial production of the ½ hard-drawn (H02 cold-worked) Cu-Ag 0.05% hollow stabilizer in continuous lengths of 325 m. The novelty of the RCOCC development concerns the assembly and the induction soft-soldering of the Rutherford cable on the Cu-Ag hollow stabilizer allowing a strict control of the interstrand contact resistance. Studies, developments, and the integration of the industrial production line at LNCMI-Grenoble are presented together with the result of the production of all RCOCC unit lengths.