Defect modes in coaxial photonic crystals

Abstract

One-dimensional (1D) photonic crystals have been constructed by connecting segments of coaxial cable of differing characteristic impedance. Impurities have been introduced into these crystals by inserting cable segments to break the crystal symmetry. This system provides a simple way to study 1D photonic band structure effects with complete control over impurities in the lattice. We have studied the effects of the size, number, and location of defects in the lattice. We have also measured directly the concentration of energy in the steady-state electromagnetic fields within doped crystals, and observed the influence of the defects on the phase (dispersion). A modified dielectric stack model was developed to describe this system, with the results in excellent agreement with our measurements. Our findings compare favorably to previously published measurements of transmission and phase change in three-dimensional photonic crystals.

Photon, electron, magnon, phonon and plasmon mono-mode circuits

“…The typical length of the cables is of the order of meter and therefore, the frequencies fall in the range of 10-500 MHz. Let us mention that, besides the papers [5,64], recent works also dealt with photonic circuits constituted by an alternative repetition of two different coaxial cables [100,101], indicating that the behaviors observed in these one-dimensional crystals are qualitatively comparable to those of photonic systems of higher dimension as well.…”

“…These serial loop structures may present large stop bands. Although they are limited to one dimension and void of polarization effects, their properties are also described by Maxwell's equations, and some linear [100,130] and nonlinear [131] properties similar to those encountered in optical photonic bandgap materials have been reported. The measurements of the amplitude and the phase of the transmission coefficients through the finite size loop structures enables to deduce several properties on the wave propagation through such structures, such as dispersion curves, phase times and, therefore, densities of states, as well as group velocities.…”

“…Several theoretical studies have dealt in the past with electromagnetic waves in superlattices with defects [109][110][111][112]. The experimental evidence of the existence of defect modes in one-dimensional photonic crystals constructed by connecting segments of coaxial cables of different characteristic impedances was presented recently by Schneider et al [100]. However, in all these studies the contrast between the dielectric constants in the two constituting layers is a critical parameter for the stop band to exist.…”

One dimensional tunable Coupled Resonator Optical Waveguide based on Liquid-Crystal layers

“…However, building microresonators by means of breaking the completeness of the structure through forming closely arranged defects will open the transmission band within the PBG [13][14][15]. This mechanism is known as Coupled Resonator Optical Waveguide (CROW) and offers unique properties for controlling the flow of light.…”

Passive system with tunable group velocity for propagating electrical pulses from sub- to superluminal velocities

“…The system under study is a conducting wire with a spatially periodic impedance, or the so-called coaxial photonic crystal which has been used recently to study effects such as photonic band gap and defect modes in the microwave spectrum [8], nonlinearities [9], and superluminal and negative pulse propagation [10][11][12]. Such a periodic structure exhibits bands of frequencies that are not allowed to propagate (or are strongly reflected) where anomalous dispersion and superluminal group velocity are observed.…”