Search results for "four wave"
showing 7 items of 7 documents
Local photo-oxidation of individual single walled carbon nanotubes probed by femtosecond four wave mixing imaging
2014
Photo-oxidation of individual, air-suspended single walled carbon nanotubes (SWCNTs) is studied by femtosecond laser spectroscopy and imaging. Individual SWCNTs are imaged by four wave mixing (FWM) microscopy under an inert gas (Ar or N2) atmosphere. When imaging is performed in an ambient air atmosphere, the decay of the FWM signal takes place. Electron microscopy shows that SWCNTs are not destroyed and the process is attributed to photoinduced oxidation reactions which proceed via a non-linear excitation mechanism, when irradiation is performed with ∼30 fs pulses in the visible spectral region (500-600 nm). Photo-oxidation can be localized in specific regions of SWCNTs within optical reso…
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…
Spatial Beam Evolution in Nonlinear Multimode Fibers
2021
We discuss some recent results illustrating the role of input wave-front shaping, propagation dynamics and output beam diagnostics in order to observe spatial beam cleaning in nonlinear multimode fibers and amplifiers.
Optical hysteresis in a semilinear photorefractive coherent oscillator
2007
International audience; High contrast optical bistability is found experimentally in the pump-ratio dependences of the output intensity of a semilinear photorefractive coherent oscillator with two counterpropagating pump waves. The data are in qualitative agreement with the results of calculation.
Broadband tuning of polarization modulation instability in microstructured optical fibers
2020
The wideband tuning of strong bands generated through polarization modulation instability (PMI) in microstructured optical fibers (MOFs) is reported. Tunability is achieved by exploiting the dependence of the phase-matching condition on the fiber’s chromatic dispersion and birefringence, which is particularly sensitive when the fiber is pumped near the zero-dispersion wavelength. MOFs designed to accomplish PMI phase-matching when they are infiltrated with ethanol and pumped at 1064 nm were designed and fabricated. Taking advantage of the large thermo-optic coefficient of ethanol, both chromatic dispersion and birefringence were varied through temperature. Wavelength shifts from 937 nm to 8…
Measurement of nonlinear and chromatic dispersion parameters of optical fibers using modulation instability
2006
International audience; We present a simple method for the measurement of Kerr, second- and third-order dispersion coefficients in optical fibers using power and dispersion dependences of modulation instability near the zero-dispersion wavelength. We also complete the analysis by the accurate determination of the zero-dispersion wavelength of the fiber using the phase-matched four wave mixing process which occurs near this specific wavelength.
On-chip quantum frequency combs for complex photon state generation (Conference Presentation)
2020
A key challenge in today’s quantum science is the realization of large-scale complex non-classical systems to enable e.g. ultra-secure communications, quantum-enhanced measurements, and computations faster than classical approaches. Optical frequency combs represent a powerful approach towards this, since they provide a very high number of temporal and frequency modes which can result in large-scale quantum systems. Here, we discuss the recent progress on the realization of integrated quantum frequency combs and reveal how their use in combination with on-chip and fiber-optic telecommunications components can enable quantum state control with new functionalities, yielding unprecedented capa…