Search results for "Mixing"
showing 10 items of 795 documents
Femtosecond four-wave-mixing spectroscopy of suspended individual semiconducting single-walled carbon nanotubes.
2010
Femtosecond four-wave-mixing (FWM) experiments of individual suspended semiconducting single-walled carbon nanotubes (SWCNTs) are presented. The chiral indices of the tubes were determined by electron diffraction as (28,14) and (24,14) having diameters of 2.90 and 2.61 nm, respectively. The diameter and semiconducting character of the tubes were additionally confirmed by resonance Raman measurements. The FWM signal showed electronic response from the SWCNTs. The results demonstrate that ultrafast dynamics of individual SWCNTs can be studied by FWM spectroscopies.
Nonlinear photo-oxidation of graphene and carbon nanotubes probed by four wave mixing imaging and spectroscopy (Presentation Recording)
2015
Graphene has high potential for becoming the next generation material for electronics, photonics and optoelectronics. However, spatially controlled modification of graphene is required for applications. Here, we report patterning and controlled tuning of electrical and optical properties of graphene by laser induced non-linear oxidation. We use four wave mixing (FWM) as a key method for imaging graphene and graphene oxide patterns with high sensitivity. FWM produces strong signal in monolayer graphene and the signal is highly sensitive to oxidation providing good contrast between patterned and non-patterned areas. We have also performed photo-oxidation and FWM imaging for air suspended carb…
CARS methane spectra: Experiments and simulations for temperature diagnostic purposes
2007
International audience; CARS laboratory experiments were done in the 2905-2925 cm(-1) range, in the vicinity of the v, band of the methane molecule, for pressures ranging from I to 50 bar, and temperatures up to 1100 K. These experiments were carried out in order to retrieve the pressure evolution of the CH4 spectrum, as well as to confirm its temperature dependance. After a brief recall on the theory used to compute pressure broadening coefficients and relaxation rates, we consider the v(3) and v(4) infrared bands of methane for benchmark calculations purposes. Next, we present recent experimental CARS spectra and calculated ones. Lastly, we discuss flame experiments as well as comparisons…
Two-wave mixing at 854 nm in BaTiO3:Rh planar waveguide implanted with He+
2001
Abstract Guided waves at 854 nm are observed in a BaTiO 3 :Rh waveguide fabricated by the technique of ion-beam implantation. The photorefractive interaction between two guided modes is demonstrated and characterized. The experiments reveal that the gain direction is reversed in the guiding layer in comparison with that in the bulk. A maximum gain of 24 cm −1 is achieved.
Phonon Bridge Effect in Superlattices of Thermoelectric TiNiSn/HfNiSn With Controlled Interface Intermixing
2020
© 2020 by the authors
Features of randomized electric-field assisted domain inversion in lithium tantalate
2011
We report on bulk and guided-wave second-harmonic generation via random Quasi-Phase-Matching in Lithium Tantalate. By acquiring the far-field profiles at several wavelengths, we extract statistical information on the distribution of the quadratic nonlinearity as well as its average period, both at the surface and in the bulk of the sample. By investigating the distribution in the two regions we demonstrate a non-invasive approach to the study of poling dynamics.
Creep–recovery and oscillatory rheology of flour-based systems
2023
The chapter reviews the application of creep-recovery and oscillatory rheological tests in flour based systems, including simple flour water systems, and more complex ones, such as bread, cookies and biscuits. A theoretical introduction about the fundaments and methods of linear viscoelastic rheology is presented, including general mathematical models and their application in flour based systems. A summary of experimental conditions to perform the rheological tests is covered. Functionality of flour based systems is extremely dependent on their viscoelastic properties. Processes like mixing, pumping, lamination, baking performance have been found to be strongly dependent on the system visco…
Improved lifetime measurements of the 3D3/2 and 3D5/2 metastable states of Ca II
1994
The lifetimes of both metastable 3D-levels of Ca+ have been measured using the ion storage technique. Operation at UHV-conditions eliminated the earlier reported problems of collisional finestructure mixing between those states [1], which is inherent to measurements at buffergas background. The results of τ(D 3/2)=1113(45) ms and τ(D 5/2)=1054(61) ms improve our earlier result [1] by almost one order of magnitude and are in good agreement with recent theoretical calculations [3, 4, 5].
Seeded intermodal four-wave mixing in a highly multimode fiber
2018
International audience; We experimentally and theoretically investigate the process of seeded intermodal four-wave mixing in a graded-index multimode fiber, pumped in the normal dispersion regime. By using a fiber with a 100-mu m core diameter, we generate a parametric sideband in the C-band (1530-1565 nm), hence allowing the use of an erbium-based laser to seed the mixing process. To limit nonlinear coupling between the pump and the seed to low-order fiber modes, the waist diameter of the pump beam is properly adjusted. We observe that the superimposed seed stimulates the generation of new spectral sidebands. A detailed characterization of the spectral and spatial properties of these sideb…
All-optical nonlinear processing of both polarization state and intensity profile for 40 Gbit/s regeneration applications
2011
International audience; In this paper, we report all-optical regeneration of the state of polarization of a 40-Gbit/s return-to-zero telecommunication signal as well as its temporal intensity profile and average power thanks to an easy-to-implement, all-fibered device. In particular, we experimentally demonstrate that it is possible to obtain simultaneously polarization stabilization and intensity profile regeneration of a degraded light beam thanks to the combined effects of counterpropagating four-wave mixing, self-phase modulation and normal chromatic dispersion taking place in a single segment of optical fiber. All-optical regeneration is confirmed by means of polarization and bit-error…