Soliton eigenvalue control with optical lattices

We address the dynamics of higher-order solitons in optical lattices, and predict their self-splitting into the set of their single-soliton constituents. The splitting is induced by the potential introduced by the lattice, together with the imprinting of a phase tilt onto the initial multisoliton states. The phenomenon allows the controllable generation of several coherent solitons linked via their Zakharov-Shabat eigenvalues. Application of the scheme to the generation of correlated matter waves in Bose-Einstein condensates is discussed.Comment: 13 pages, 4 figures, to appear in Physical Review Letter

Stabilization of vector solitons in optical lattices

We address the properties and dynamical stability of one-dimensional vector lattice solitons in Kerr-type cubic medium with harmonic transverse modulation of refractive index. We discovered that unstable families of scalar lattice solitons can be stabilized via the cross-phase modulation (XPM) in the vector case. It was found that multi-humped vector solitons that are unstable in uniform media where XPM strength is higher than that of self-phase modulation, can also be stabilized by the lattice.Comment: 14 pages, 4 figures. To appear in Physical Review E, vol. 7

Tunable optical sorting and manipulation of nanoparticles via plasmon excitation

We numerically investigate the optical forces exerted by an incident light beam on Rayleigh metallic particles over a dielectric substrate. In analogy with atom manipulation, we identify two different trapping regimes depending on whether the illumination is performed within the plasmon band or out of it. By adjusting the incident wavelength, the particles can be selectively guided, or immobilized, at the substrate interface. © 2006 Optical Society of America OCIS codes: 140.7010, 240.5420, 260.3910, 240.0240. Due to their potential confinement down to subwavelength volumes, evanescent fields bound at interfaces open novel opportunities for efficient manipulation of nano-objects. 1-4 Lately, we have shown both theoretically and experimentally that plasmon fields at a metal/dielectric interface can be used to dramatically enhance the optical forces on a dielectric object. We consider a metal sphere immersed in water ͑n water = 1.33͒, floating at 15 nm from the surface of a heavy flint glass prism ͑n flint = 1.8͒. The illumination is performed from the glass under total internal reflection (TIR) by either a plane wave or a tightly focused three-dimensional Gaussian beam [see 9 This formalism accounts for multipolar contributions, which cannot be neglected for metal particles of diameter larger than a few tens of nanometers. Due to their dispersion, the optical forces that experience metal nanoparticles under illumination are susceptible to dramatic variations with the incident wavelength. For a small dielectric particle, using a dipolar approximation, the total force combines a gradient contribution that attracts the particle towards the highest field value and a scattering component that tends to push it along the incident wave vector. In the case of absorbing particles, an absorption force is added to the scattering component. The evolution with the incident wavelength of the X and Z components of the total force exerted on an 80 nm diameter gold sphere is shown i

Stable multicolor periodic-wave arrays

We study the existence and stability of cnoidal periodic wave arrays propagating in uniform quadratic nonlinear media and discover that they become completely stable above a threshold light intensity. To the best of our knowledge, this is the first example in physics of completely stable periodic wave patterns propagating in conservative uniform media supporting bright solitons.Comment: 12 pages, 3 figure