There are two figures of merit used to assess the suitability of a nonlinear material for all-optical switching devices [8]. If the loss is dominated by linear absorption, W = A n l a must be larger than unity. In PTS, W > 1 for I > 20MW/cm2, based on attenuation coefficients estimated from those reported by Thakur, Frye and Greene [9]. In the case where two-photon absorption dominates the loss...

We report on a novel method based on intracavity spontaneous mode locking to precisely measure the group refractive indices and temperature dependence of refractive index of Nd:YVO(4) crystal at the wavelength of 1064 nm. All the experimental results are found to agree very well with the most recent measured values. We also confirm that the developed method is applicable to measuring the group ...

The thermal contribution to the nonlinear refractive index of air at 1.064mum was measured with a high-finesse Fabry-Perot cavity and a 500-mW cw laser beam. At room temperature and pressure, the nonlinear refractive-index coefficient of air was found to be n(2)((th))=(-1.9+/-0.2)x10 (-14) cm(2)/W for a beam waist radius of 0.23 mm and was found to be independent of the relative humidity. The t...

Nonlinear refractive index, n of an undoped z-cut photorefractive LiNbO3 crystal has been investigated here by the Z-scan technique using a continuous wave (cw) laser beam from a multiline argon-ion laser. Here both the sign and magnitude of the measured n are considerably different from the reported z-scan result in LiNbO3 obtained with picoseconds pulsed laser at 532 nm but in good agreement ...

An application of the method of approximate inverse to a two-dimensional inverse scattering problem is discussed. The determination of the refractive index from an inverse scattering experiment is a nonlinear inverse problem. In this paper we treat the 2D scalar case. We propose to split this nonlinear problem into an ill-posed linear problem and a (well-posed) nonlinear part by rst solving the...

An application of the method of approximate inverse to a two-dimensional inverse scattering problem is discussed. The determination of the refractive index from an inverse scattering experiment is a nonlinear inverse problem. In this paper we treat the 2D scalar case. We propose to split this nonlinear problem into an ill-posed linear problem and a (well-posed) nonlinear part by rst solving the...

We demonstrate experimentally a transition from nonlinear beam trapping to defocusing in a two-dimensional periodic photonic structures by varying the modulation depth of the lattice. The observed effect illustrates the fundamental crossover from discrete to cw transport mechanisms. At the threshold modulation, the output beam is highly sensitive to refractive index and power variations, which ...

We address the existence and properties of optical solitons excited in thermal nonlinear media with a transverse refractive index gradient. The interplay between the nonlocality of the thermal nonlinearity and the linear refractive index enables generating controllable switching from surface soliton propagating near the sample edges to bulk solitons. Beam steering associated with the different ...

We report for the first time to our knowledge optical waveguiding in an organic crystalline waveguide produced by ion implantation. Using H+ ions a refractive index barrier suitable for waveguiding has been realized in the highly nonlinear optical organic crystal 4-N, N-dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST). The refractive index changes in the waveguiding region as a function ...