We study coherent backscattering of a monochromatic laser by a dilute gas of cold two-level atoms in the weakly nonlinear regime. The nonlinear response of the atoms results in a modification of both the average field propagation (nonlinear refractive index) and the scattering events. Using a perturbative approach, the nonlinear effects arise from inelastic two-photon scattering processes. We p...

We analyze experimentally light scattering from chi(2) nonlinear gratings and observe two types of second-harmonic frequency-scattering processes. The first process is identified as Raman-Nath type nonlinear diffraction that is explained by applying only transverse phase-matching conditions. The angular position of this type of diffraction is defined by the ratio of the second-harmonic waveleng...

Imaging highly complex subsurface structures is a challenging problem because it ultimately necessitates dealing with nonlinear multiple-scattering effects (e.g., migration of multiples, amplitude corrections for transmission effects) to overcome the liminations of linear imaging. Most of the current migration techniques rely on the linear single-scattering assumption, and therefore, fail to ha...

Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus have potential applications in nonlinear optics, which requires extraordinary optical intensity. One of the most studied nonlinearities in plasmonics is nonlinear absorption, including saturation and reverse saturation behaviors. Although scatt...

We present algorithms for feature extraction from complex SAR imagery. The features parameterize an attributed scattering center model that describes both frequency and aspect dependence of scattering centers on the target. The scattering attributes extend the widely-used point scattering model, and characterize physical properties of the scattering object. We present two feature extraction alg...

We detected the second-order nonlinear response from single isolated spheres comprised from a centrosymmetric material but covered by a layer of a material with strong second-order nonlinear properties and isolated from an ensemble by the optical trapping technique. We show that when large size parameter spheres are used, the measured second-harmonic efficiency deviates strongly from the predic...

Inverse Compton scattering sources are finding increasing use as intense of high-energy photons. When operated at high field strength, ponderomotive detuning the scattered emission can lead to decreased source performance. Up now, calculations spectra for such nonlinear Thomson have been done assuming a perfectly aligned electron interacts with incident laser beam and several authors investigat...