Waveguide construction

Asymmetric conductors have isymmetric I — V curves. This phenomenon is known as the diode or ratchet effect and plays a major role in electronics. Recently much interest has been attracted by transport asymmetries in singlemolecule devices and other mesoscopic systems [1], The idea that asymmetric molecules can be used as rectifiers is rather old [2], however, it was implemented experimentally [3] only recently. Another experimental realization of a mesoscopic rectifier is an asymmetric electron waveguide constructed within the inversion layer of a semiconductor heterostructure [4]. The ratchet effect was observed in carbon nanotubes [5], and strongly asymmetric I — V curves were recently reported for the tunneling in the quantum Hall edge states [6]. These experimental advances have stimulated much theoretical activity [7, 8, 9, 10, 11] with the main focus on the simplest Fermi-liquid systems [12]. 

Applications include eye glasses, spatial light modulation [31], optical waveguide construction [32], nonlinear optical switching [33], inks, and paints. 

Accordion polymers—Continued orientational and chemical stability, 139 synthesis by Knoevenagel condensation polymerization, 135-136 waveguide construction, 139-140 Aluminum metal electrode, deposition on polymer in LED, 411,412/ Aromatic amine-containing polymers dye-dispersed poly(N-vinylcarbazole), 387, 390-393... 

In the previous sections we assumed the waveguides were constructed from isotropic material. We now consider waveguides constructed from anisotropic material. For perspective, we first treat plane-wave propagation in an unbounded, uniform anisotropic medium. Then we discuss the modes of anisotropic waveguides. 

Consider waveguides constructed from anisotropic or, equivalently, crystalline material with the properties discussed in Section 11-23. For simplicity, we assume that the three principal axes of the dielectric medium are parallel to the three geometrical axes of the isotropic waveguide. The spatial variation of the refractive-index profile can differ for each polarization direction. For light polarized in the x-direction, the waveguide is characterized by the refractive-index profile nx(x,y) and associated parameters A, and while for light polarized entirely in the y-direction it is characterized by the profile n, (x, y) and associated parameters A, and Vy, where... 

Now we modify the early sections of this chapter to include weakly guiding waveguides constructed from the anisotropic material discussed above, i.e. = = = n. To do this, we first recall from Section 11-23 that the two... 

The construction of the optoelectronic interface can be based on a silicon photodiode since analytical and reference wavelengths are from the visible and the IR regions, respectively. The signals can be filtered out by optical filters (then two photodiodes are required) or one photodiode can be synchronised with modulation waves of the LEDs used. Finally, silica optical fibres can be used as light waveguides. The choice between single fibre or bundle is determined by the application of the sensor. 

Optical sensors (Figure 1) can be defined as devices for optical monitoring of physical parameters (pressure1, temperature2, etc.) or (bio)chemical properties of a medium by means of optical elements (planar optical waveguides or optical fibres). Chemical or biochemical fibre-optic sensors3 are small devices capable of continuously and reversibly recording the concentration of a (bio)chemical species constructed be means of optical fibres. 

It is well known that the low refractive index of water (n = 1.33) causes problems for the construction of optical waveguides that guide light efficiently through... 

Using the LB technique, one can control the film thickness and the molecular arrangement along the film normal at molecular level. These features are very useful for the construction of sophisticated nonlinear waveguide with high... 

Construction of waveguide or optical-fiber fluorosensors usable for medical diagnoses. 

The FMM mode solver for circularly bent waveguides can be constructed in a very similar way as for straight waveguides. The cross-section of a bent waveguide is schematically depicted in Fig. 8. We will suppose that the cross-section of an azimuthally invariant waveguide can be subdivided into... 

The remaining part of the mode seeking procedure can formally proceed exactly in the same as for the straight waveguide starting from both innermost and outermost slices, two values of the immittance matrix in some suitably chosen radial position p are found and are then used to construct the set of homogeneous linear equations for the mode field amplitudes ... 

Fibre optic-based flow-through optical biosensors The dramatic advances in fibre optic development in die last decade have promoted construction of sensors where radiation, whether emitted, transmitted or reflected, is conducted fi-om the sample to the detection system. The wide variety of available optical waveguide types (solid rods, hollow cylinders, micro-planar geometries) has been used with varying success in sensor development. 

This paper describes the luminoscope, a simple laboratory-constructed, portable luminescence detector designed specifically for monitoring occupational skin contamination. The instrument design is based upon a fiberoptics waveguide. The instrument is suitable for detecting trace amounts of various coal tars and has recently been field tested at a coal conversion facility. 

All of our natural experience with optics occurs in the linear domain. In order to apply nonlinear optics in practice, light must first interact with the NLO material. In our laboratories, free space interconnections are usually employed for this purpose. That is, a laser beam is aimed at the material under examination. In any practical use of NLO, such simplistic solutions will not be possible, for reasons both of safety and rugged construction of the device. Light will need to be moved around in space within the device. In many second order devices, whether they are color-specific lasers, such as doubled diode or YAG lasers, or EO modulators such as spatial light modulators (SLM s) waveguide or fiber optic connections will be used. Aspects of these materials will not be reviewed. 

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