Search results for "nonlinear optics"
showing 10 items of 482 documents
Tunable Four-wave Mixing Light Source Based on Photonic Crystal Fibers with Variable Chromatic Dispersion
2019
We present a detailed experimental study of fourwave mixing tuning in photonic crystal fibers that were filled either with ethanol or with heavy water. It is demonstrated that wide tuning ranges can be achieved in both cases through the variable chromatic dispersion generated by thermo-optic effect. Tunability of the signal band from 745 nm to 919 nm, and of the idler band from 1260 nm to 1759 nm is demonstrated with a pump at 1064 nm. Numerical calculations were carried out and show good agreement with experimental measurements. We present a detailed experimental study of fourwave mixing tuning in photonic crystal fibers that were filled either with ethanol or with heavy water. It is demon…
Fourth-order cascaded Raman shift in AsSe chalcogenide suspended-core fiber pumped at 2 μm
2011
International audience; Cascaded Raman wavelength shifting up to the fourth order ranging from 2092 to 2450nm is demonstrated using a nanosecond pump at 1995nm in a low-loss As38Se62 suspended-core microstructured fiber. These four Stokes shifts are obtained with a low peak power of 11W, and only 3W are required to obtain three shifts. The Raman gain coefficient for the fiber is estimated to (1.6 +-0.5)x 10e−11 m/W at 1995nm. The positions and the amplitudes of the Raman peaks are well reproduced by the numerical simulations of the nonlinear propagation.
Triphenyl group containing molecular glasses of azobenzene for photonic applications
2016
Abstract D-π-A type organic molecules have attracted considerable attention of scientists due to their potential applications in nonlinear optics and holographic data storage as light, flexible and low-cost photonic materials. To provide a better understanding on the relation between the compound chemical structure and their physical properties necessary for the mentioned purposes, eight glassy triphenyl group containing derivatives of azobenzene with incorporated 5,5-dimethylcyclohex-2-enylidene or 4H-pyran-4-ylidene structural fragments and dicyanomethylene, indene-1,3-dione and pyrimidine-2,4,6(1H,3H,5H)-trione acceptor groups have been synthesized and investigated. Thermal stability of …
Enhanced photorefractive properties of Bi-doped Sn2P2S6
2008
International audience; Enhanced photorefractive properties of tin hypothiodiphosphate (Sn2P2S6) crystals as a result of Bi doping are presented. These new crystals were obtained by the vapor-transport technique using stoichiometric Sn2P2S6 composition with an additional amount of Bi up to 0.5 mol. % in the initial compound. The bandgap edges of the obtained crystals are located at ~750 nm and shift toward the red wavelengths with increasing Bi concentration. Sn2P2S6:Bi crystals are found to exhibit larger two-beam coupling gain coefficients (up to 17 cm−1 at a wavelength of 854 nm) as compared to (i) pure Sn2P2S6 (2.5 cm−1 at 854 nm), (ii) Sn2P2S6 crystals modified by the growth conditions…
Pre-determining the location of electromigrated gaps by nonlinear optical imaging
2014
In this paper we describe a nonlinear imaging method employed to spatially map the occurrence of constrictions occurring on an electrically-stressed gold nanowire. The approach consists at measuring the influence of a tightly focused ultrafast pulsed laser on the electronic transport in the nanowire. We found that structural defects distributed along the nanowire are efficient nonlinear optical sources of radiation and that the differential conductance is significantly decreased when the laser is incident on such electrically-induced morphological changes. This imaging technique is applied to pre-determined the location of the electrical failure before it occurs.
Determination of temperature by stimulated raman scattering of molecular nitrogen, oxygen, and carbon dioxide
1993
We have determined the temperature from SRS spectra of N2-N2, N2-CO2, O2-O2, and CO2-CO2 recorded in wide pressure and temperature ranges. The fitting procedure takes simultaneously into account the Dicke effect and motional narrowing. We have quantified the accuracy of the MEG and ECS-P models for rotational relaxation. The temperature extracted from each model is compared with thermocouple measurements. The influence of vibrational broadening and shifting is discussed in detail.
Continuous-wave backward frequency doubling in periodically poled lithium niobate
2010
We report on backward second-harmonic-generation in bulk periodically poled congruent lithium niobate with a 3.2 microns period. A tunable continuous-wave Ti:sapphire laser allowed us exciting two resonant quasi-phase-matching orders in the backward configuration. The resonances were also resolved by temperature tuning and interpolated with standard theory to extract relevant information on the sample.
Theory of parabolic pulse propagation in nonlinear dispersion decreasing optical fiber amplifiers
2008
Optical fibers ; Nonlinear optics ; Optical fiber amplifiers ; Optical amplifier ; Optical solitons ; Electromagnetic wave propagation ; Pulse propagation ;; International audience; We show that pulse spectral broadening in normally dispersive nonlinear fiber amplifiers may be enhanced by introducing a suitable dispersion tapering. We obtain an analytical dispersion profile that permits one to reduce pulse propagation in a varying dispersion fiber to the case of an equivalent fiber with constant parameters.
Modular approach to obtaining organic glasses from low-molecular weight dyes using 1,1,1-triphenylpentane auxiliary groups: Nonlinear optical propert…
2013
Abstract A new modular synthetic approach to obtain organic glasses from low-molecular weight azobenzenes and stilbenes has been accomplished using 1,1,1-triphenylpentane crystallization preventing auxiliary groups. Six new structures show excellent solubility in non-polar solvents and thin films with good optical qualities have been obtained using a spin-coating technique. The glass transition temperatures of the new amorphous materials were in the range of 73–108 °C. The nonlinear optical activity in thin amorphous films was measured after a corona poling procedure.
Proton exchange channel waveguides compatible with surface domain engineering in Lithium Niobate crystals
2006
First experiments of proton exchange channel waveguides compatible with electric field surface periodic poling of congruent lithium niobate crystals are addressed. Picosecond nonlinear copropagating QPM-SHG measurements have been carried out on such structures.