in this article, the effect of cells' radius on the behavior of wavelength switching optical filter andthe effect of the radius of the optical filters' key characteristics such as wavelength resonance onan optical filter based on photonic crystals, have been investigated. currently, the most commonapplied mechanism for designing optical filter based on photonic crystals is using twomechanisms s...

in this paper, a resonant slotted waveguide array antenna with circular boundary has been designed and simulated for mono-pulse airborne radar applications. the antenna parameters are:11% bandwidth in x-band (8.6-9.6ghz),vswr < 2, 38dbi directivity, sidelobes level of - 20db and 3-db beam-widths of 2.1degree. to design this antenna, it is divided into short sections (sub-arrays) each with a uni...

The prime focus of this chapter is a hollow optical waveguide for integrated optics. Starting with a review of various novel hollow waveguide structures, physics and technology of tunable hollow waveguide have been presented with theory and experiments. With the flexible structure of hollow waveguide, a number of tunable optical functions can be realized; some of them are presented in the chapt...

We demonstrate the feasibility of the process for fabricating a single-mode waveguide and a large-core multimode waveguide aligned vertically on the same substrate. Using this process, we propose and demonstrate a filter that drops optical signal propagating in a single-mode waveguide to a multimode waveguide in the specific wavelength interval by a long-period grating. We use perfluorocyclobut...

in this paper, the output power behavior of the wave-guide cw-co2 laser versus efficient parameters of laser performance was investigated. the output power variation versus the discharge current, the pressure and the gas mixture ratio was studied and optimized. the maximum output powers of 6 and 14.5 w were respectively obtained at operating pressures 78 and 50 mbar in two tubes of 3 mm same di...

We study adiabatic transformation in optical waveguides with discrete translational symmetry. We calculate the reflection and transmission coefficient for a structure consisting of a slab waveguide that is adiabatically transformed into a photonic crystal waveguide and then back into a slab waveguide. The calculation yields high transmission over a wide frequency range of the photonic crystal w...

Twisted hollow waveguides with noncircular cross sections may be considered as slow-wave structures. In a twisted waveguide, propagating radio frequency (rf) waveguide modes can have phase velocities slower than those of similar modes in a straight waveguide. This property is interesting since a twisted waveguide basically has a uniform cross section along the propagation direction. In such a w...

As neurons age, their survival depends on eliminating a growing burden of damaged, potentially toxic proteins and organelles-a capability that declines owing to aging and disease factors. Here, we review the two proteolytic systems principally responsible for protein quality control in neurons and their important contributions to Alzheimer disease pathogenesis. In the first section, the discove...

Waveguide array lenses are waveguide arrays that focus light incident on all waveguides at the input side into a small number of waveguides at the output side. Ideal waveguide array lenses provide complete (100%) power concentration of incident light into a single waveguide. While of great interest for several applications, ideal waveguide array lenses have not been demonstrated for practical a...

We present the experimental observation of a spatial vector soliton formed by counterpropagation of coherent optical fields. This is to our knowledge the first observation of a vector soliton in which the induced waveguide (potential) is periodic in the propagation direction. This vector soliton induces a waveguide and a thick grating within the waveguide, which can be used as a tunable optical...