Resonant light scattering by optical solitons

We consider the process of light scattering by optical solitons in a planar waveguide with homogeneous and inhomogeneous refractive index cores. We observe resonant reflection (Fano resonances) as well as resonant transmission of light by optical solitons. All resonant effects can be controlled in experiment by changing the soliton intensity.     

Resonant quasi-resonant solitons

Propagation of an optical pulse in a set of transitions created by simple Zeeman splitting is investigated. It is shown that resonant and nonresonant circularly polarized components repel one another, while a coupled soliton state can be formed only between quasi-resonant components whose planes of polarization rotate in opposite directions.     

Resonant control of solitons

It is shown that the effect of “scattering on resonance” can be used to control envelope solitons in the driven nonlinear Schrödinger equation. The control occurs by the frequency modulated driving with multiple crossing of the resonant frequency of the soliton.     

Resonant Raman scattering in germanium

We have studied the spectral dependence of the first order Raman scattering cross section of Ge at room and liquid nitrogen temperatures in the energy region containing the E₁ and E₁ + Δ₁ optical gaps. This region was covered by a fine mesh of points obtained from the discrete lines of three gas lasers and a cw continuously tunable dye laser. Only one resonant peak was observed, as opposed to the two peaks that characterise the absorption and reflection spectra in this region. The shape of this resonance peak can be explained as due to the changes in the electronic polarizability produced by phonon-induced wave function mixing of the spin-orbit split Λ valence band doublet. The observed temperature shift in the resonant energy is much smaller than the one predicted from the known shifts of the optical gaps with temperature. Furthermore the resonant peak at room temperature appears shifted to higher energies when compared with the theoretical peak calculated from the room temperature optical constants. The resonant Raman peak appears to shift with increasing temperature by the full thermal expansion effect plus only a fraction of the electron-phonon interaction shift seen in the optical constants.     

Resonant and nonresonant optical solitons: Similarities and differences

An analysis of the similarities and differences between resonant and nonresonant optical solitons is conducted. The study focuses on physical aspects of the problem, including self-focusing and self-defocusing. Attention is given to possible applications of both types of solitons in optical information transmission and processing systems.     

Resonant interband scattering of image-potential states

Image-potential states in front of a clean Cu (100) surface were investigated by time- and angle-resolved two-photon photo-emission (2PPE). We observe a previously unknown quasi-elastic relaxation channel, which efficiently couples states with different quantum numbers, n, and parallel momenta, k_∥. This process of resonant interband scattering (RIS) is independent of sample temperature and shows a close relationship to the pure dephasing of image-potential states. Received: 1 October 2001 / Revised version: 24 October 2001 / Published online: 23 November 2001     

Resonant rayleigh scattering in semiconductor structures

Il Nuovo Cimento D - A detailed study of the relative role played by localized and/or propagating intermediate excitonic states in, resonant Rayleigh scattering (RRS) is presented for a large set...     

Resonant Bhabha scattering at MeV energies

We discuss, on a phenomenological level, the possible appearance of resonances ine ⁺+e ^? scattering at energies in the MeV region. The expected resonance cross section and angular distribution are examined. The observability depends crucially on the attainable energy resolution which is limit by the momentum distribution of the electrons contained in the target.     

Resonant multiphonon Raman scattering in AgBr

Resonant Raman scattering in AgBr single crystals is studied at low temperatures. Excitation in resonance with the indirectΓ — L exciton as intermediate state gives rise to selectively enhanced narrow two-phonon Raman scattering. The phonons involved are pairs ofLA andTO phonons of opposite wavevectors near theL-point. A simple model involving one discrete exciton level is developed to explain the resonance behaviour. The temperature dependence of the scattered intensity, that is studied for 1.8 K <T < 35 K, can consistently be interpreted within this model as being due to the lifetime of the intermediate state. Assuming that the excitons predominantly decay by one-phonon scattering with long wavelength acoustical phonons the predicted temperature dependence of the intensity is found in good agreement with the experimental result. Additional scattering peaks are believed to be due to third-order processes involving an acousticalX-phonon in addition to theL-phonons of the second-order scattering. Using an oriented sample the resonant Raman peaks are found to be polarized.     

Resonant solitons in semiconductors: Transparency induced by exciton-exciton interactions

Propagation of femtosecond light pulses spectrally centered at the 1s-exciton resonance in a semiconductor is studied analytically and numerically. Soliton-like propagation is demonstrated for pulses with the input area exceeding a certain threshold. This phenomenon is shown to be different from the self-induced transparency in atomic systems and associated with the formation of the resonant solitons due to exciton-exciton interactions.     

Energy of scattering solitons in the Ward model

We present the results derived in our paper [Proc. Royal. Soc. Lond. A 461 (2005) 1965], where we have shown that the energy density of a scattering-soliton solution in Ward's integrable chiral model is the same as the energy density of a static multi-lump solution of the ℂP ³ sigma model. This explains the quantization of the total energy in the Ward model. Presented at the International Colloquium “Integrable Systems and Quantum Symmetries”, Prague, 16–18 June 2005.     

Numerical simulation of scattering of solitons, dark solitons, and vortices by potential walls

Scattering of solitons, dark solitons, and vortices by a potential wall are numerically studied with the Gross-Pitaevskii equation. A transition from reflection to the transmission occurs as the velocity of the localized solutions is increased. The critical energy for the transmission is generally rather smaller than the critical energy for a classical particle. The localized objects can penetrate into the potential wall easily, and this is interpreted as coherent tunneling.     

Resonant and non-resonant soliton scattering by impurities

The NLSE soliton scattering by impurities is considered in the framework of the one-dimensional model. The scattering intensity is characterized by the reflection coefficient of the soliton is calculated in the Born approximation of the perturbation theory for the following cases: (i) and isolated impurity, (ii) two point impurities, and (iii) a regular or random system of point impurities. An analytical comparison with the scattering of linear waves is carried out. In particular, we analytically describe the nonlinear resonant scattering by two point impurities, and the non-resonant soliton scattering by a random system of point impurities.     

Resonant absorption and scattering in evanescent fields

Received: 14 July 1998