Search results for "Kerr effect"
showing 10 items of 107 documents
Determination of Kerr and two-photon absorption coefficients of ABI thin films
2018
This material is based upon work supported by the ERDF 1.1.1.1 activity project Nr. 1.1.1.1/16/A/046 “Application assessment of novel organic materials by prototyping of photonic devices”
Spatial beam self-cleaning in multimode fibres
2017
Multimode optical fibres are enjoying a renewed attention, boosted by the urgent need to overcome the current capacity crunch of single-mode fibre systems and by recent advances in multimode complex nonlinear optics [1-13]. In this work, we demonstrate that standard multimode fibres can be used as ultrafast all-optical tool for transverse beam manipulation of high power laser pulses. Our experimental data show that the Kerr effect in a graded-index multimode fibre is the driving mechanism for overcoming speckle distortions, leading to a somewhat counter-intuitive effect resulting in a spatially clean output beam robust against fibre bending. Our observations demonstrate that nonlinear beam …
Electrostrictive cross-phase modulation of periodic pulse trains in optical fibers
1998
Electrostriction-induced cross-phase modulation between subsequent bits of a nonreturn-to-zero pulse train in optical fibers leads to nonlinear frequency shifts of opposite sign for the 1’s and the 0’s. Direct experimental measurements of the electrostrictive and Kerr-induced nonlinear phase shift across the bit profiles agree well with the theoretical modeling.
Highly efficient few-mode spatial beam self-cleaning at 15µm
2020
We experimentally demonstrate that spatial beam self-cleaning can be highly efficient when obtained with a few-mode excitation in graded-index multimode optical fibers. By using 160 ps long, highly chirped (6 nm bandwidth at -3dB) optical pulses at 1562 nm, we demonstrate a one-decade reduction of the power threshold for spatial beam self-cleaning, with respect to previous experiments using pulses with laser wavelengths at 1030-1064 nm. Self-cleaned beams remain spatio-temporally stable for more than a decade of their peak power variation. The impact of input pulse temporal duration is also studied.
Non-Linear Optical Properties of Hybridized Surface Plasmon Polaritonic Crystals: Observation of Optical Bistability
2007
Summary form only given. The use of surface plasmons (SP) is recognized as being central to the development of nanoscale assemblies of photonic and opto-electronic devices. This is motivated by the spatially confined nature of these electromagnetic waves as well as their resonant behavior. Amongst plasmonic supporting structures, surface plasmonic crystals (SPCs) draw particular interest because of their tailored optical properties. A geometry common to SPCs consists in a periodic arrangement of holes or slits in a metal film. Their complex optical response is then governed by coherent interactions between Bloch modes at the film's interfaces and modes supported by the holes or slits. These…
Magnetic and structural investigations of ultra-thin Co–Fe alloy films on W(1 1 0)
2004
Abstract We investigated ultra-thin CoxFe1−x films on a flat and vicinal BCC W(1 1 0) surface with thicknesses between 1.8 and 7 monolayers (ML) using longitudinal Kerr magnetometry. We found a transition from magnetic bulk behavior between 3 and 4 ML to the monolayer. The maximum of the remnant Kerr signal that appears for thicker films at x=0.5 turns into a minimum for a sample thickness below 4 ML , while the specific Kerr-rotation per monolayer shows the well known bulk behavior. A similar magnetic behavior on the flat as well as on the stepped part of the substrate indicates that this is an intrinsic property. For x=0.5 the pseudomorphic monolayer is paramagnetic even when it is covere…
Self-assembled monolayers on a ferromagnetic permalloy surface.
2015
Self-assembled monolayers (SAMs) are nowadays broadly used as surface protectors or modifiers and play a key role in many technological applications. This has motivated the study of their formation in all kind of materials; however, and despite the current interest in molecular spintronics, the study of SAMs on ferromagnetic surfaces remains almost unexplored. In this paper, we report for the first time a methodology for the formation of SAMs of n-alkylphosphonic acids on permalloy in ambient conditions. The formed monolayers have been fully characterized by means of contact angle measurements, atomic force microscopy, X-ray photoelectron spectroscopy, matrix assisted laser desorption ioniz…
EoP250. Recent advances in transparent ferroelectric ceramics research and applications
1992
Abstract The studies of field-induced lattice rearrangement and field-induced phase transition (PT), laser beam effects in transparent ferroelectric ceramics (TFC), dopant and radiation effects in PLZT, Kerr effect demonstration and application of an intracavity matrix-addressed spatial-time modulator are discussed.
Nonlinear interaction of light with Bose-Einstein condensate: new methods to generate subpoissonian light
2004
We consider $\Lambda$-type model of the Bose-Einstein condensate of sodium atoms interacting with the light. Coefficients of the Kerr-nonlinearity in the condensate can achieve large and negative values providing the possibility for effective control of group velocity and dispersion of the probe pulse. We find a regime when the observation of the "slow" and "fast" light propagating without absorption becomes achievable due to strong nonlinearity. An effective two-level quantum model of the system is derived and studied based on the su(2) polynomial deformation approach. We propose an efficient way for generation of subpoissonian fields in the Bose-Einstein condensate at time-scales much sho…
Higher-order Kerr effects improve quantitative modelling of harmonics generation and laser filamentation
2013
The consideration of the higher-order Kerr effect (HOKE) drastically improves the quantitative agreement between measured and simulated harmonic yield as well as intensity and electron density in laser filaments generated by pulses below a few hundreds of fs. In longer pulses, the plasma defocusing plays a much more important role.