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We create extended longitudinally optically bound chains of microparticles with the use of counterpropagating ``nondiffracting'' light fields, the so-called Bessel beams. The beam homogeneity and extended propagation range allow the creation of $200\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ long chains of organized microparticles. We observe short-range multistability within a single chain and long-range multistability between several distinct chains. Our observations are supported by theoretical results of the coupled dipole method.

A Comment on the Letter by Marc Guillon, Olivier Moine, and Brian Stout, [Phys. Rev. Lett. 96, 143902 (2006)]. The authors of the Letter offer a Reply.

Optical binding along the axis of two counterpropagating laser fields may be used to organize microparticles into longitudinal, spatially separated, arrays. Here we investigate correlations between the displacements of two optically bound microparticles from their equilibrium positions due to noise. Measurement of the decay time of the correlation functions of the center of mass and relative normal modes is shown to provide an in situ method to determine the optical restoring forces acting on the bound particles, thereby providing a test of our physical understanding of longitudinal optical binding.

The temperature dependence of the frequencies and linewidths of the Raman-active longitudinal optical (LO) phonons in GaAs and AlAs have been measured. The low-temperature lifetime of the LO phonon in AlAs is found to be 9.7 ps, very close to the corresponding GaAs value of 9.5 ps. This contradicts early theoretical predictions. The agreement between theory and experiment can be restored when the accidental degeneracy between the AlAs LO phonon frequency and a feature in the two-phonon density of states is taken into account.

The discretization of the electronic spectrum in semiconductor quantum dots implies a strong coupling behavior between the optical phonons and the electron-hole pairs, despite the fact that a pair is electrically neutral. The excitonic polarons strongly modify the optical spectra. In particular, the ground excitonic polaron contains one or two phonon components, which leads to the existence of phonon replicas in the luminescence. The population and coherence decay times of the optical transition associated with the ground excitonic polaron are calculated.

We present a computational proof for the puzzling experimental vibrational density of states in MgO nanocrystals measured by neutron scattering. For the first time, the experimental peak of longitudinal optical modes in the high frequency region is theoretically reproduced and traced back to surface inward relaxation. Practically perfect agreement of theory with the experiment demonstrates the importance of nanocrystal size effects. Dependence of the transversal optical model on the volume/surface ratio is also verified. Strong (up to 2%) buckling of nanocrystal faces is found. Our calculations show varieties of relaxation shapes for clusters, shedding light on contradictory data on nanocrystals and infinite surfaces.

We show that longitudinal optical (LO) vibrational modes account for several previously unexplained peaks in the Raman spectra of vitreous Ge${\mathrm{O}}_{2}$ and Si${\mathrm{O}}_{2}$. Identification of LO modes in these and other glasses reduces the complexity of the spectra that must be explained by simple structural models. It also follows that long-range (Coulomb) forces should be included in complete theories of the vibrational properties of many glasses.

Exciton line splitting in MgO and BeO induced by exciton-phonon coupling, comparing splitting with longitudinal optical phonon energy

Les interferences ont lieu pres des resonances. Application a la surface (100) pres de la bande interdite E 0 +Δ 0 de GaAs