We study the charge dynamics and electronic structure by optical spectroscopy technique. Here we focus on the following four issues: (1) the evolution of optical spectra with Na content; (2) the spectral features specific to different regions in the phase diagram; (3) the c-axis optical response for crystal at the A-type antiferromagnetic region; (4) the optical response of misfit-layered Bi2M2...

We calculate the linear optical response from a single quantum dot molecule and the nonlinear, four-wave-mixing response from an inhomogeneously broadened ensemble of such molecules. We show that both optical signals are affected by the coupling-dependent superradiance effect and by optical interference between the two polarizations. As a result, the linear and nonlinear responses are not ident...

We have measured nonlinear scattering from plasmons in individual Au nanorods and have correlated second-harmonic activity of Ag nanoparticles and clusters to morphology. The measurements reveal novel ultrafast nonlinear phenomena related to electron confinement. Surprisingly, the coherent plasmon response is suppressed relative to the hot electron response indicating enhanced plasmon dephasing...

We study the nonlinear optical response of a fishnet structure-metamaterial all-optical switching device that exhibits two near-infrared negative-index resonances. We study and compare the nonlinear optical response at both resonances and identify transient spectral features associated with the negative index resonance. We see a significantly stronger response at the longer wavelength resonance...

We present the first experimental study of the optical properties of HELP InGaAsP (InGaAsP grown by He-plasma-assisted molecular beam epitaxy) relevant to all-optical switching, and the first demonstration of picosecond switching using this material. We observed an optical response time of 15 ps, a nonlinear index change as large as 0.077, a sharp absorption band edge, and a small absorption ta...

We consider hybrid optical devices consisting of a waveband (transparent optical) and a wavelength (opaque OEO) switch. Such hybrid devices are suitable for supporting hierarchical optical paths (wavelength and waveband paths). We study the node-level costperformance tradeoffs using both analytical models and simulations. The results demonstrate a significant cost reduction that could be achiev...

Several centuries ago the overarching obstacle in the evolution of vision was documented when George Berkeley pointed out that information in retinal images cannot be mapped unambiguously back onto their real-world sources. In this experiment, we used the EEG to analyze the brainwave dates of 2 stimuli, one can cause human optical illusion, but the other cannot. The purpose of this work was to ...

In this paper, a modulated optical injection system is proposed. It mainly consists of a semiconductor laser subject to a modulated optical injection. It is known that optical injection will force a laser intensity into high-speed periodic oscillation without modulation, while the oscillation will be locked with weak external modulation. However, the route to chaos in such a system is observed ...

Precise knowledge of an optical device's frequency response is crucial for it to be useful in most applications. Traditional methods for determining the frequency response of an optical system (e.g. optical cavity or waveguide modulator) usually rely on calibrated broadband photo-detectors or complicated RF mixdown operations. As the bandwidths of these devices continue to increase, there is a ...

a comprehensive study on the structural, electronic and nonlinear optical (nlo) properties of alumina nanostructures (al2o3)n with n = 2-5 belonging to the groups iii and vi dopants carried out by density functional theory. the nbo charges exhibit dopant atoms caused to the increasing charge transfer and introduces acceptor-donor model for nlo response of alumina nanostructures. under the influ...