An application of the method of approximate inverse to a two-dimensional inverse scattering problem is discussed. The determination of the refractive index from an inverse scattering experiment is a nonlinear inverse problem. In this paper we treat the 2D scalar case. We propose to split this nonlinear problem into an ill-posed linear problem and a (well-posed) nonlinear part by rst solving the...

We examined the spherical equivalent refractions of 237 subjects who had been seen four or more times in a longitudinal study of refractive development in normal children. We employed both photorefraction and autorefraction using a Canon R1 autorefractor. We performed an analysis of variance (F-test for Lack of Fit) to determine the significance of a linear regression in fitting these refractio...

This paper deals with a group velocity dispersion issue and a peak reflectivity issue in a non-uniform fiber Bragg gratings (FBG) due to an arbitrary refractive index profile along the length of grating. The paper shows that by using more complicated refractive index profile one can significantly reduce the group velocity dispersion and side lobes intensity and that in main lobe the bandwidth o...

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...

We present a method for calculating a two-dimensional refractive index field from measured boundary values of beam position and slope. By initially ignoring the dependence of beam trajectories on the index field and using cubic polynomials to approximate these trajectories, we show that the inverse problem can be reduced to set of linear algebraic equations and solved using a numerical algorith...

We design a terahertz (THz) metal-dielectric-metal (MDM) waveguide sensor with embedded microfluidic channel suitable for sensing the refractive index variations in liquid. The transmission properties are described using transmission line model (TLM) and numerically simulated using finite-difference time domain (FDTD) method. The sensing characteristics of the structure are systematically analy...

In this paper, we review the principal theoretical models through which the dielectric function of metals can be described. Starting from the Drude assumptions for intraband transitions, we show how this model can be improved by including interband absorption and temperature effect in the damping coefficients. Electronic scattering processes are described and included in the dielectric function...

Stabilization of silicon micro-resonators is a key requirement for their inclusion in larger photonic integrated circuits. In particular, thermal refractive index shift in non-linear applications can detune devices from their optimal working point. A cavity stabilization scheme using a micro-processor-based feedback control loop is presented based on a local thermal heater element on-chip. Usin...