Fabrication of Tapers and Lenslike Waveguides by a Microcontrolled Dip Coating Procedure

A technique for the fabrication of tapered and lenslike waveguides from solution-deposited thin films is described. Using a microprocessor controlled dipping arm, substrates are withdrawn from a solution with a carefully controlled and varying velocity. In this way optical waveguides with regions of varying thickness are deposited. Following the drying and baking of the films, desired structures are obtained in hard inorganic optical waveguides of good optical quality. With refined profile control, we propose to fabricate other optical waveguide components, for example, thin film lenses with this method

Solution Deposited Optical Waveguide Lens

The development of a solution deposited optical waveguide lens, whose focusing effect is produced by an effective index gradient with a hyperbolic secant variation, is described. The lenses are fabricated by a microcontrolled dip coating procedure from colloidal SiO2:TiO2 solutions. Both the design and construction of the lens, along with the analytical and experimental results of the focusing properties, are described. The best lenses had speeds of ~ƒ/10 and focal spots ~1.2 times the diffraction limit at apertures of 2.0 mm

Generalized Dispersion Properties of Thin-Film Waveguides

The dispersion properties of a thin-film optical waveguide for TE and TM modes are expressed in simple and general analytic forms. These formulas describe the variation of the effective refractive index with respect to any physical parameter with which the refractive index of any layer or the thickness of the guiding layer may vary. Universal curves for both TE and TM modes are given, and applications of the formulas are discussed

Thermally stable low current consuming gallium and germanium chalcogenides for consumer and automotive memory applications

The phase change technology behind rewritable optical disks and the latest generation of electronic memories has provided clear commercial and technological advances for the field of data storage, by virtue of the many well known attributes, in particular scaling, cycling endurance and speed, that chalcogenide materials offer. While the switching power and current consumption of established germanium antimony telluride based memory cells are a major factor in chip design in real world applications, often the thermal stability of the device can be a major obstacle in the path to the full commercialisation. In this work we describe our research in material discovery and characterization for the purpose of identifying more thermally stable chalcogenides for applications in PCRAM

The transition from quantum field theory to one-particle quantum mechanics and a proposed interpretation of Aharonov-Bohm effect

In this article we demonstrate a sense in which the one-particle quantum mechanics (OPQM) and the classical electromagnetic four-potential arise from quantum field theory (QFT). In addition, the classical Maxwell equations are derived from a QFT scattering process, while both classical electromagnetic fields and potentials serve as mathematical tools to approximate the interactions among elementary particles described by QFT physics. Furthermore, a plausible interpretation of the Aharonov-Bohm (AB) effect is raised within the QFT framework. We provide a quantum treatment of the source of electromagnetic potentials and argue that the underlying mechanism in the AB effect can be understood via interactions among electrons described by QFT where the interactions are mediated by virtual photons.Comment: 19 pages, 2 figures. Final published versio

Lithography assisted fiber-drawing nanomanufacturing

We present a high-throughput and scalable technique for the production of metal nanowires embedded in glass fibres by taking advantage of thin film properties and patterning techniques commonly used in planar microfabrication. This hybrid process enables the fabrication of single nanowires and nanowire arrays encased in a preform material within a single fibre draw, providing an alternative to costly and time-consuming iterative fibre drawing. This method allows the combination of materials with different thermal properties to create functional optoelectronic nanostructures. As a proof of principle of the potential of this technique, centimetre long gold nanowires (bulk Tm = 1064°C) embedded in silicate glass fibres (Tg = 567°C) were drawn in a single step with high aspect ratios (>104); such nanowires can be released from the glass matrix and show relatively high electrical conductivity. Overall, this fabrication method could enable mass manufacturing of metallic nanowires for plasmonics and nonlinear optics applications, as well as the integration of functional multimaterial structures for completely fiberised optoelectronic devices

In-fiber all-optical modulation based on an enhanced light-matter interaction with graphene

A graphene-based, high speed, in-fiber optical modulator has been demonstrated on a low-loss side-polished optical fiber platform. These results highlight the potential for robust and efficient integration of low-dimensional materials within standard telecom fibers

Graphene-based fiber polarizer with PVB-enhanced light interaction

Graphene is a two-dimensional material which, as a result of its excellent photonic properties, has been investigated for a wide range of optical applications. In this paper, we propose and fabricate a commercial grade broadband graphene-based fiber polarizer using a low loss side-polished optical fiber platform. A high index polyvinyl butyral layer is used to enhance the light-graphene interaction of the evanescent field of the core guided mode to simultaneously obtain a high extinction ratio ~37.5 dB with a low device loss ~1 dB. Characterization of the optical properties reveals that the polarizer retains low transmission losses and high extinction ratios across an extended telecoms band. The results demonstrate that side-polished fibers are a useful platform for leveraging the unique properties of low-dimensional materials in a robust and compact device geometry

Electrical properties of Bi-implanted amorphous chalcogenide films

The impact of Bi implantation on the conductivity and the thermopower of amorphous chalcogenide films is investigated. Incorporation of Bi in Ge-Sb-Te and GeTe results in enhanced conductivity. The negative Seebeck coefficient confirms onset of the electron conductivity in GeTe implanted with Bi at a dose of 2x1016 cm-2. The enhanced conductivity is accompanied by defect accumulation in the films upon implantation as is inferred by using analysis of the space-charge limited current. The results indicate that native coordination defects in lone-pair semiconductors can be deactivated by means of ion implantation, and higher conductivity of the films stems from additional electrically active defects created by implantation of bismuth.Comment: This is an extended version of the results presented in Proc. SPIE 8982, 898213 (2014

Study of TMDs nanosheets based saturable absorber used for Q-switching and mode lock laser system

Pulse width of pulsed laser determinates their applications. For the long pulse laser with µs or ns pulse width, it can be used for telecommunication, remote sensing and medical surgery. For the ultrashort pulse laser with ps or fs pulse width, it can be used for eye-surgery, precise micro- or even nano-machining on transparent material and novel 3D hologram formation. The saturable absorber (SA) is the crucial optical component that switch the laser operation from CW mode to pulse mode passively. Therefore it attract s great research interests from the laser photonic community. &more..