The optical spectra of thiolated Au25(SR)18/Au23(SR)16 clusters with different R residues are investigated via TDDFT simulations. Significant enhancements in the optical region and effective electron delocalization are simultaneously achieved by tuning the ligands' steric hindrance and electronic conjugating features, producing a resonance phenomenon between the Au-S core motif and the ligand f...

A new optical device for wavelength auto-router was proposed. Such a structure is useful in the integratedoptic for optical operation and data communication. We use the finite-difference beam propagation method to investigate the phenomenon of the proposed numerical model.

Novel conical reflection of light by a thick three-layered metal-clad optical waveguide is observed. A symmetrical metal-cladding optical waveguide is used, which exhibits extraordinary conical reflection during free-space coupling of light to the waveguide. The phenomenon is attributed to the leakage of excited ultrahigh-order guided modes and their inter- and intramode coupling interaction.

Optical burst amplification in a gain-stabilized amplifier may generate complex gain dynamics with nonlinear behavior. This phenomenon is thoroughly investigated by using a theoretical model and dedicated experiments. Design guidelines for optimized devices avoiding optical burst transmission impairments are proposed.

New tools from Infrared Space Observatory (ISO) mid-infrared spectroscopy have recently become available to determine the power sources of dust-obscured ultraluminous infrared galaxies (ULIRGs). We compare ISO classiications { starburst or active galactic nucleus (AGN) { with classiications from optical spectroscopy, and with optical/near-infrared searches for hidden broad-line regions. The agr...

New tools from Infrared Space Observatory (ISO) mid-infrared spectroscopy have recently become available to determine the power sources of dust-obscured ultraluminous infrared galaxies (ULIRGs). We compare ISO classifications – starburst or active galactic nucleus (AGN) – with classifications from optical spectroscopy, and with optical/near-infrared searches for hidden broad-line regions. The a...

A series of recent articles have presented results demonstrating optical cooling of macroscopic objects, highlighting the importance of this phenomenon for investigations of macroscopic quantum mechanics and its implications for thermal noise in gravitational wave detectors. In this Letter, we present a measurement of the off-resonance suspension thermal noise of a 1 g oscillator, and we show t...

Graphene has received significant attention due to its excellent properties currently. In this work, a nano-optomechanical system based on a doubly-clamped Z-shaped graphene nanoribbon (GNR) with an optical pump-probe scheme is proposed. We theoretically demonstrate the phenomenon of phonon-induced transparency and show an optical transistor in the system. In addition, the significantly enhance...

We examine paraxial propagation of recently introduced optical coherence lattices in free space and demonstrate a novel phenomenon of periodicity reciprocity between their intensity and coherence properties. The periodicity reciprocity arises because an aperiodic source intensity profile of an optical coherence lattice evolves into a lattice-like far-field profile, while the periodic spectral d...

copper films (250 nm) deposited on glass substrates, at different substrate temperatures. their optical properties were measured by ellipsometery (single wavelength of 589.3 nm) and spectrophotometery in the spectral range of 200–2600 nm. kramers kronig method was used for the analysis of the reflectivity curves of cu films to obtain the optical constants of the films, while ellipsometery measu...