1. The photonic-crystal fibres In conventional optical fibres, electromagnetic modes are guided by a phenomenon of total internal reflection on a core-cladding border. The core refractive index is higher than the refractive index of a cladding which is achieved by adequate doping of a central part of the based material [1]. After over 20 years of intense researches on optical fibres, including ...

Using optical levitation of individual 3-10-/Lm droplets, we investigate the resonance structure of the light intensity scattered at an angle of approximately 900 by a dielectric droplet, a slightly absorbing droplet, and composite inhomogeneous droplets. We find in all the cases that the resonance structures of dielectric, weakly absorbing, and composite inhomogeneous spheres are almost identi...

Two-dimensional near-field images of light transmitted through a disordered dielectric structure have been measured for two probe wavelengths. From these data, the 2D spatial dependence of the intensity correlation function, C(deltaR-->), has been extracted. We observe that the spatial dependence of C is dominated by a rapidly varying feature determined by the wavelength of the probe light and ...

This work addresses a new configuration that improves the sensitivity of a humidity sensor based on a long-period fiber grating coated with a SiO(2)-nanospheres film. An intermediate higher refractive index overlay, deposited through Electrostatic Self-Assembly, is placed between the fiber cladding and the humidity sensitive film in order to increase the total effective refractive index of the ...

We report on a novel nondestructive and reversible method for coupling free space light to planar optical waveguides. In this method, an elastomeric grating is used to produce an effective refractive index modulation on the surface of the optical waveguide. The external elastomeric grating binds to the surface of the waveguide with van der Waals forces and makes conformal contact without any ap...

The absolute phase refractive index n relates the phase velocity v in matter to the vacuum light velocity c(n » civ). It is determined by the molecular polarizability of the medium and gives insight to the interaction of light with matter and the structure of substances. 3 Additionally the group refractive index ng is needed to describe light pulse propagation, 4 5 which is defined as the ratio...

A theoretical investigation is made of the effects of dispersion in neutral gases on the formation of white-light fringes in an ideal Mach-Zehnder interferometer. It is found that the shift of the brightest fringe is determined by the change of the group refractive index at an effective mean wavelength of the white light. However, the white-light fringe technique may be used to measure changes ...

The effective medium refractive index of a surface-bound submonolayer of polystyrene nanospheres in water is found to be ill-defined below a rather specific sphere occupied area limit. The submonolayer takes on a recognizable thickness and refractive index only when the average center separation between spheres is at or below the inverse of the wavenumber. An anticipated limit to the Maxwell Ga...

A novel reflective refractometer based on a thin-core fiber (TCF) sandwiched between a leading single-mode fiber (SMF) and a fiber Bragg grating (FBG) imprinted SMF stub was demonstrated. The reflection from the fiber stub occurs in two well-defined wavelength bands, corresponding to the Bragg core mode and cladding modes. The TCF section functions as a tailorable bridge between the FBG core mo...

On the basis of a full-vectorial three-dimensional Maxwell-Bloch approach we investigate the possibility of using gain to overcome losses in a negative refractive index fishnet metamaterial. We show that appropriate placing of optically pumped laser dyes (gain) into the metamaterial structure results in a frequency band where the nonbianisotropic metamaterial becomes amplifying. In that region ...