Ultra-compact branchless plasmonic interferometers

Miniaturization of functional optical devices and circuits is a key prerequisite for a myriad of applications ranging from biosensing to quantum information processing. This development has considerably been spurred by rapid developments within plasmonics exploiting its unprecedented ability to squeeze light into subwavelength scale. In this study, we investigate on-chip plasmonic systems allowing for synchronous excitation of multiple inputs and examine the interference between two adjacent excited channels. We present a branchless interferometer consisting of two parallel plasmonic waveguides that can be either selectively or coherently excited via ultra-compact antenna couplers. The total coupling efficiency is quantitatively characterized in a systematic manner and shown to exceed 15% for small waveguide separations, with the power distribution between the two waveguides being efficiently and dynamically shaped by adjusting the incident beam position. The presented design principle can readily be extended to other configurations, giving new perspectives for highly dense integrated plasmonic circuitry, optoelectronic devices, and sensing applications.Comment: 15 pages, 6 figure

Design and Validation of a Framework for the Creation of User Experience Questionnaires

Existing user experience questionnaires have a fixed number of scales. Each of these scales measures a distinct aspect of user experience. These questionnaires can be used with little effort and provide a number of useful support materials that make the application of such a questionnaire quite easy. However, in practical evaluation scenarios it can happen that none of the existing questionnaires contains all scales necessary to answer the research question. It is of course possible to combine several UX questionnaires in such cases, but due to the variations of item formats this is also not an optimal solution. In this paper, we describe the development and first validation studies of a modular framework that allows the creation of user experience questionnaires that fit perfectly to a given research question. The framework contains several scales that measure different UX aspects. These scales can be combined to cover the relevant research questions

Construction of a Benchmark for the User Experience Questionnaire (UEQ)

Questionnaires are a cheap and highly efficient tool for achieving a quantitative measure of a product’s user experience (UX). However, it is not always easy to decide, if a questionnaire result can really show whether a product satisfies this quality aspect. So a benchmark is useful. It allows comparing the results of one product to a large set of other products. In this paper we describe a benchmark for the User Experience Questionnaire (UEQ), a widely used evaluation tool for interactive products. We also describe how the benchmark can be applied to the quality assurance process for concrete projects

What Causes the Dependency between Perceived Aesthetics and Perceived Usability?

Several studies reported a dependency between perceived beauty and perceived usability of a user interface. But it is still not fully clear which psychological mechanism is responsible for this dependency. We suggest a new explanation based on the concept of visual clarity. This concept describes the perception of order, alignment and visual complexity. A high visual clarity supports a fast orientation on an interface and creates an impression of simplicity. Thus, visual clarity will impact usability dimensions, like efficiency and learnability. Visual clarity is also related to classical aesthetics and the fluency effect, thus an impact on the perception of aesthetics is plausible. We present two large studies that show a strong mediator effect of visual clarity on the dependency between perceived aesthetics and perceived usability. These results support the proposed explanation. In addition, we show how visual clarity of a user interface can be evaluated by a new scale embedded in the UEQ+ framework. Construction and first evaluation results of this new scale are described

Applicability of User Experience and Usability Questionnaires

To be successful, interactive products need to fulfil user expectations and create a positive user experience (UX). An established method to measure UX involves questionnaires. What we aim in this paper is to present a list of user experience and usability questionnaires and its applicability for different digital products. A total of 13 questionnaires on usability and UX were analysed for this paper, and 25 factors were extracted from those questionnaires. A study was conducted based on this collection of factors with N=61 students. The study investigated the perceived importance of usability and UX factors for seven digital products. The goal was to have a collection of usability and UX factors that could be combined for suitable products evaluation. The results of the study revealed that no questionnaire covered all the factors perceived important by the participants

A Benchmark for the UEQ+ Framework: Construction of a Simple Tool to Quickly Interpret UEQ+ KPIs

Questionnaires are a highly efficient method to compare the user experience (UX) of different interactive products or versions of a single product. Concretely, they allow us to evaluate the UX easily and to compare different products with a numeric UX score. However, often only one UX score from a single evaluated product is available. Without a comparison to other measurements, it is difficult to interpret an individual score, e.g. to decide whether a product’s UX is good enough to compete in the market. Many questionnaires offer benchmarks to support researchers in these cases. A benchmark is the result of a larger set of product evaluations performed with the same questionnaire. The score obtained from a single product evaluation can be compared to the scores from this benchmark data set to quickly interpret the results. In this paper, the first benchmark for the UEQ+ (User Experience Questionnaire +) is presented, which was created using 3.290 UEQ+ responses for 26 successful software products. The UEQ+ is a modular framework that contains a high number of validated user experience scales that can be combined to form a UX questionnaire. Currently, no benchmark is available for this framework, making the benchmark constructed in this paper a valuable interpretation tool for UEQ+ questionnaires

Construction of UEQ+ scales for voice quality: measuring user experience quality of voice interaction

The UEQ+ is a modular framework for the construction of UX questionnaires. The researcher can pick those scales that fit his or her research question from a list of 16 available UX scales. Currently, no UEQ+ scales are available to allow measuring the quality of voice interactions. Given that this type of interaction is increasingly essential for the usage of digital products, this is a severe limitation of the possible products and usage scenarios that can be evaluated using the UEQ+. We describe in this paper the construction of three specific scales to measure the UX of voice interactions. Besides, we discuss how these new scales can be combined with existing UEQ+ scales in evaluation projects