Ultrafast laser inscription is a standard technique to fabricate embedded waveguides in glasses or crystals. Tightly focused femtosecond laser-pulses induce an increase in refractive index inside the material via non-linear absorption. By moving the sample through the focus virtually arbitrary threedimensional paths can be created. The transfer of this technique to polymers has already delivere...

A non-rotationally symmetric encapsulation shape - which takes advantage of the low reflection coefficient for transverse magnetic polarized light near Brewster's angle - designed to enhance extraction of a particular desired linear polarization from an unpolarized source is reported. The algorithm for optimization of the shape is described. Numerical ray-tracing simulations of the encapsulatio...

The quantitative errors of extinction efficiency during the particulate measurement caused by the refractive index are studied. And the quantitative results are acquired when the real part of the refractive index and the imaginary part change respectively. The change ranges of the real part are 1+0.5 i to 2+0.5 i at a 0.1 interval and 1.5+0.5 i to 1.59+0.5 i at a 0.01 interval. Another the chan...

A new type long period fiber grating is fabricated in all-solid photonic bandgap fiber by periodically drilling microholes using femtosecond laser pulse irradiation. Such a structure introduces a strong refractive index modulation in the waveguide structure and hence exhibits a compact grating dimension. Both the simulation and the experimental results confirm the existence of the light couplin...

the goal of this research is to predict total stock market index of tehran stock exchange, using the compound method of arima and neural network in order for the active participations of finance market as well as macro decision makers to be able to predict trend of the market. first, the series of price index was decomposed by wavelet transform, then the smooth's series  predicted by using...

We investigate the effects of the refractive index of the encapsulant on the light-extraction efficiency (LEE) of light-emitting diodes (LEDs) for GaN LEDs (n ≈ 2.5) and AlGaInP LEDs (n ≈ 3.0). For non-absorbing rectangular parallelepiped LED chips, as the refractive index of the encapsulant increases, the LEE first increases quasi-linearly, then increases sub-linearly, and finally a saturation...

We suggest the use of the refractive-index changes associated with the intersubband transitions in quantum wells for phase matching in nonlinear materials. An improvement in the conversion efficiency of mid-IR second-harmonic generation by almost 2 orders of magnitude over non-phase-matched bulk GaAs is predicted. We also show that the linear phase contributions of intersubband transitions used...

Numerical studies of beam filamentation in laser-produced plasma are presented. This involves the numerical solution of the parabolic wave equation. known as the Schrodinger equation, coupled with the thermal transport equations for both ions and electrons, in two dimensions. The solutionof the resultingequationwith non-linear refractive index due to thermal and pondermotive forces. shows self-...