Book Review: Alternative and Activist New Media

Alternative and Activist New Media. Digital Media and Society Series. By Leah A. Lievrouw. Pp. 294. USA/England, Polity Press, 2011. ISBN-13: 978-0-7456-4184-3 (pb)

Planar micromachined glass cantilevers utilising integrated Bragg Fabry-Perot cavities

Here we demonstrate a glass cantilever based on a unique micromachining and etching approach, combined with UV written Bragg gratings. We shall also discuss the increase in sensitivity by using two Bragg gratings to form Fabry-Pérot cavity. Cantilevers are in ultra sensitive force sensors used in applications such as Atomic Force Microscopy, mass sensing and acoustic transducers

Lateral groove geometry for planar UV written evanescent devices - new flexibility new devices

Conventional evanescent optical devices have made use of etched windows to allow access of an optical field to a material of interest. Such devices are a route to accurate refractive index sensors and to realising modulators, however, the geometry of etching the cladding to give the fluid access to a pre-defined core waveguide mode is limiting. In this work, we present an alternative approach in which a groove is cut using a polishing saw blade to give a vertical, high optical quality trench. Optical waveguides are then UV written to allow evanescent lateral access of the mode to a fluid placed in the trench. This seemingly subtle change in geometry provides greatly increased flexibility to tailor the interaction between the optical mode and the surrounding material, by, for example, changing the mode size and the allowing couplers or tapers to be used

New geometry for planar UV written refractive index sensors

We shall present some of our recent results from our work on UV written planar waveguide refractive index sensors. Refractive index of an analyte is measured through the perturbation of an optical mode, interrogation of the modal index is achieved via the reflected spectra from a Bragg grating defined in the same process as the channel waveguide. Here we introduce a new geometry which embraces the benefits of planar technology to realise new integrated devices. The geometry allows several different sensors to be defined on the same substrate each offering complementary information. Such information may include index as a function of penetration depth for surface binding analytes, interrogation wavelength for dispersion analysis, enhanced sensitivity in specific index ranges and temperature compensation. We shall also outline the inherent fabrication advantages and device feature benefits, including a reduction in return loss, spectral artefacts and a suggested reduction in stress induced birefringence. The silica sensing surface opposed to gold used in SPR devices opens new avenues to exploit surface binding. With a marked reduction in complexity and cost these devices may have significant impact in future sensor markets

Flat-top temperature tuning response in periodically-poled nonlinear crystals

Second harmonic generation via periodically-poled nonlinear materials offers an efficient means of generating high-quality visible light that would be otherwise unattainable with traditional laser sources. While this technology has the potential for implementation in many mass-industrial applications, temperature stability requirements of 0.1 deg.C can make packaging with a pump source problematic. Using our high fidelity poling technique we have achieved precise placement of poled domains in Lithium Niobate based on the resulting mathematical models. These initial devices provide more than 4 deg.C flat-top temperature stability, albeit with a corresponding loss in operational efficiency. Our aim is to implement improved designs in magnesium-doped Lithium Niobate for packaging with near-room temperature diode-based pump sources, as could be applied towards RGB TV and projector applications

Consumer Behaviour Analysis and the Behavioural Perspective Model

This is the FIRST of TWO linked articles on consumer behavioural analysis. Cognitive theories have dominated the field of consumer behaviour for the last few decades, however, an observed lack of consistency between attitudes and behaviour has suggested the need to investigate more thoroughly situational and behavioural variables. Consumer behaviour analysis can be viewed as an alternative theoretical approach that emphasizes situational variables and measures of behaviour. Within consumer behaviour analysis, the Behavioural Perspective Model (BPM) interprets consumer behaviour as occurring at the intersection of the individual’s learning history and the consumer setting, which signals utilitarian and informational consequences associated with consumption-related responses. Utilitarian consequences are mediated by the product or service and are related to its functional benefits. Informational consequences are social, mediated by other people, and are related to feedback upon consumers’ behaviour, such as social status and prestige

Consumer Behaviour Analysis and Consumer Brand Choice

This is the SECOND of TWO linked articles on consumer behavioural analysis dealing with the Behavioural Perspective Model, which locates consumer behaviour at the intersection of the consumer’s learning history and the consumer situation. As an example of research inspired by the Model, this article presents investigations into consumers’ patterns of brand choice, showing how brand repertoires are formed and how brands are selected within those repertoires

100 GHz electrically tunable planar Bragg grating via nematic liquid crystal overlay towards reconfigurable WDM networks

Novel liquid crystal-based integrated optical devices with >140GHz electrical tuning are presented for application towards reconfigurable wavelength division multiplexing (WDM) networks. Initial results with Bragg wavelength tuning covering five 25GHz WDM channel spacing have been achieved with 170V (peak-to-peak) sinusoidal voltages applied across electro-patterned ITO-covered glass electrodes placed 60µm apart. These prototype devices were fabricated using direct UV grating writing, with an evanescent field coupling into a liquid crystal overlay through an etched window. Electrically controlled liquid crystal birefringence modifies the waveguide effective index, resulting in Bragg wavelength shift. Merck 18523 nematic liquid crystals are used, exhibiting compatible refractive index values to that of silica (no=1.44, ne=1.49 at lambda=1550nm). Homeotropic alignment of the liquid crystal is provided by application of a surfactant layer.The inherent refractive index sensitivity of our etched direct-UV-written structures allows observation of previously unreported liquid crystal surface-behaviour, such as multi-threshold points during variation of the applied field. Continued optimisation based on evanescent field penetration, electrode layout, and surface interaction will allow implementation towards a variety of novel liquid crystal applications and devices. For example, a cascaded architecture of these integrated liquid crystal devices operating at different Bragg wavelengths would pave the way towards true colorless add/drop modules for dense optical networks

Consumer-based brand equity and brand performance

The relation between consumer-based brand equity and brand performance was investigated across 15 product categories in Brazil and the UK. Brand equity was conceptualized as related to the level of social benefit offered by each brand and was measured with a simple questionnaire that asked consumers to rate brands with respect to their familiarity and quality levels. These measures were then related to brand market share and revenue. Results showed that the relation between consumer-based brand equity and brand performance varies across product categories, indicating that products differ with respect to their level of brandability and suggesting ways to measure it

Direct grating writing: single-step Bragg grating and waveguide fabrication for telecommunications and sensing applications

Direct Grating Writing (DGW) has been developed over the past decade as a means of rapidly prototyping waveguides with integrated Bragg grating structures in silica-on-silicon substrates [1]. The technique allows complicated waveguide structures and Bragg grating arrays to be fabricated and characterised in house