Search results for "Refractive"
showing 10 items of 559 documents
Interferometric Phase Retrieval in Optical Transient Detection
2021
A transient detection imaging system (TDI), also known as optical novelty filter, is an adaptive interferometric device that detects temporal changes in a scene while suppressing its static parts. Removal of background improves contrast and helps visualizing and measuring intensity and phase. Following the first TDI proposal by Cudney et al. [1] , most TDI systems are based on photorefractive two-wave mixing [2] . Previous works rely on conventional intensity measurements, where partial information about input signal phase changes are obtained by previous calibration using an input phase-output intensity transfer function of the particular system.
Observation of collapse arrest in pure kerr media sustained by a parametric interaction
2013
We demonstrate a parametric interaction based on four wave mixing that can arrest the collapse and stabilize solitary propagation in a pure Kerr material by controlling the wavelength of the interacting beams.
Two frequency oscillation of a photorefractive oscillator as a perturbation of the mirrorless oscillation
2010
We consider the properties of the non-degenerate two frequency regime of oscillation of the semi-linear photorefractive oscillator and analyze its relation with the mirrorless oscillation. We consider the oscillator with or without a frequency shifted feedback by a vibrating mirror. This study shows that these two apparently different phenomena are closely related. We conclude from the obtained results that the two frequency oscillation can be considered as a perturbation of the mirrorless oscillation.
Soliplasmon excitations at metal/dielectric/Kerr structures
2009
We present novel optical phenomena based on the existence of a new type of quasi-particle excitation in metal/dielectric/Kerr structures. We discuss the possibility of excitation of surface plasmon polaritons via spatial solitons in these systems.
Parametric coherent oscillation with feedback via an orthogonally polarized wave
1999
Coherent light amplification with photorefractive crystals may be a consequence of several frequency degenerate (or nearly degenerate) processes of nonlinear wave mixing : It appears for two- beam coupling in the crystals with diffusion-driven charge transport [1] or transport via circular photovoltaic currents [2].
Large-signal enhanced frequency conversion in birefringent optical fibers: theory and experiments
1998
Strong frequency conversion among light waves propagating in a low-birefringence optical fiber in the normal-dispersion regime is experimentally investigated. Modulational gain spectra are obtained by injection of a signal orthogonally polarized with respect to a pump beam aligned with the slow fiber axis. Measurements reveal that, for signal power levels above a certain threshold value, peak conversion is obtained at pump signal frequency detunings far from the phase-matching condition. The large-signal three-wave mixing regime is well described by integrable nonlinear coupled-wave equations.
Anisotropic elasto-optic effect in optical fibers under axial strain: a perturbative approach
2016
We present a perturbative approximation to calculate the relative shift of the WGM resonances in a conventional optical fibers when an axial strain is applied. We consider the anisotropic character of the elasto-optic effect.
Solitons in Optical Fibers
1996
In the near future nonlinear optics should probably revolutionize the world of telecommunications and computer technologies. With lasers producing highintensity and short-duration optical pulses, it is now possible to probe the interesting, and potentially useful, nonlinear effects in optical systems and waveguides. Among the guiding structures, the optical fiber is an interesting (Gloge 1979) and important device (Mollenauer and Stolen 1982; Doran and Blow 1983). In an optical transmission system using linear pulses, the bit rate of transmission is limited by the dispersive character of the material, which causes the pulse to spread out an eventually overlap to such an extend that all the …
Surface Reconstruction of Transparent Objects by Polarization Imaging
2008
This paper focuses a method to acquire the surface of transparent objects for 3D measurement. The technique relies on the so called ?Shape from Polarization? technique. The principle of this polarization imaging technique is as follows: after being reflected, an unpolarized light becomes partially linearly polarized. The surface normals can be evaluated by analyzing their polarization parameters and by knowing the refractive index of the object to be controlled. Finally, the 3D shape is obtained by integrating the normals field. After an introduction to expose the problematic, section 2 exposes the principles of polarization technique. The third and the last section deal with the polarimetr…
Photorefractive amplifier-converter and coherent oscillator with nonexponential gain
2001
For some parametric interactions with identically zero exponential gain for the signal wave the intensity of the idler wave can grow as a second power of the propagation coordinate. Such an amplification is revealed for the parametric mixing of four copropagating waves in BaTiO3; two of them are ordinarily polarized and the two others are extraordinarily polarized. This mixing is used to build up a coherent oscillator. A reasonable qualitative agreement of the experimental results with the calculated data is demonstrated.