Looking to score: the dissociation of goal influence on eye movement and meta-attentional allocation in a complex dynamic natural scene

Several studies have reported that task instructions influence eye-movement behavior during static image observation. In contrast, during dynamic scene observation we show that while the specificity of the goal of a task influences observers’ beliefs about where they look, the goal does not in turn influence eye-movement patterns. In our study observers watched short video clips of a single tennis match and were asked to make subjective judgments about the allocation of visual attention to the items presented in the clip (e.g., ball, players, court lines, and umpire). However, before attending to the clips, observers were either told to simply watch clips (non-specific goal), or they were told to watch the clips with a view to judging which of the two tennis players was awarded the point (specific goal). The results of subjective reports suggest that observers believed that they allocated their attention more to goal-related items (e.g. court lines) if they performed the goal-specific task. However, we did not find the effect of goal specificity on major eye-movement parameters (i.e., saccadic amplitudes, inter-saccadic intervals, and gaze coherence). We conclude that the specificity of a task goal can alter observer’s beliefs about their attention allocation strategy, but such task-driven meta-attentional modulation does not necessarily correlate with eye-movement behavior

Trained Eyes: Experience Promotes Adaptive Gaze Control in Dynamic and Uncertain Visual Environments

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This work was supported by grants from Engineering and Physical Sciences Research Council (EP/F069626/1)

Sensitivity enhancement in optical waveguide sensors using metamaterials

We consider a four-layer waveguide structure as an optical waveguide sensor. One of the layers is a metamaterial with negative permittivity and permeability. We show that the sensitivity of the proposed optical waveguide sensor can be dramatically enhanced by using a metamaterial layer between the guiding and the cladding layers. The variation of the sensitivity of the proposed waveguide sensor with different parameters of the waveguide is studied

Theoretical spectroscopic scan of the sensitivity of asymmetric slab waveguide sensors

An extensive theoretical analysis is carried out to investigate the variation of the sensitivity of optical slab waveguide sensors with the wavelength of the guided wave. We consider a three-layer waveguide as an optical sensor. The sensitivity for both polarizations of light: s-polarized light (TE) and p-polarized light (TM), is derived using the characteristic equation of the structure. The dispersion of the materials is taken into account to study the sensitivity spectroscopic scan over the near IR-range from 1.2–2 µm. It is found that an optimum wavelength exists for each guiding layer thickness and this optimum value increases linearly with the thickness of the guiding layer

Slab Waveguide Sensor with Left-handed Material Core Layer for Detection an Adlayer Thickness and Index

A four-layer slab waveguide structure with a lossy left-handed material (LHM) core layer is investigated as a surface sensor for detection any change in an adlayer thickness and refractive index. The sensitivities of the effective refractive index to any change in the refractive index/thickness of the adlayer are derived and studied with the parameters of the LHM. It is found that a slight change in the real parts of the permittivity and permeability of the LHM can significantly improve the sensitivity of the proposed sensor

Comparing optical sensing using slab waveguides and total internal reflection ellipsometry

The sensitivity of the effective refractive index of slab waveguide sensors to variations in the refractive index of the cladding is compared to that of the ellipsometric parameters. The changes of the effective refractive index of a waveguide and the ellipsometric parameter\Delta, due to the index change of the cladding, were derived and plotted as a function of the guiding layer thickness and with the index of the cladding. It is found that these changes almost have the same overall feature but the ellipsometric parameters showed considerable higher sensitivity than the effective index of the conventional waveguide optical sensors

Development and construction of rotating polarizer analyzer ellipsometer

A detailed mathematical derivation and an experimental characterization of one to two ratio rotating polarizer analyzer ellipsometer (RPAE) are presented. The alignment, calibration, and testing of reference samples are also discussed. The optical properties of some known materials obtained by the proposed ellipsometer will be shown and compared to accepted values. Moreover, the constructed ellipsometer will be tested using two ellipsometry standards with different thicknesses

Dispersion properties of slab waveguides with double negative material guiding layer and nonlinear substrate

The dispersion properties of transverse electric nonlinear waves in a three-layer slab waveguide which consists of a double negative material (DNM) guiding layer sandwiched between an intensity-dependent refractive index substrate and semi-infinite linear dielectric cover are investigated. The dispersion properties for self-focusing and self-defocusing substrate nonlinearity are presented. The effects of the negative parameters of the DNM on the dispersion characteristics are investigated

Dispersion properties of anisotropic-metamaterial slab waveguide structure

The dispersion properties of guided waves in an anisotropic film sandwiched between a left-handedmaterial (LHM) and a dielectric are investigated in this work. Detailed mathematical derivationof the dispersion relation is presented. Both the anisotropic guiding layer and the LHM are assumedto be dispersive. Many interesting features have been found. The dispersion properties exhibita slight dependence on the parameters of the anisotropic guiding layer whereas they showa significant change with any perturbation in some of the LHM layer parameters, especially forω>5.2GHz.The dispersion properties of guided waves in an anisotropic film sandwiched between a left-handedmaterial (LHM) and a dielectric are investigated in this work. Detailed mathematical derivationof the dispersion relation is presented. Both the anisotropic guiding layer and the LHM are assumedto be dispersive. Many interesting features have been found. The dispersion properties exhibita slight dependence on the parameters of the anisotropic guiding layer whereas they showa significant change with any perturbation in some of the LHM layer parameters, especially forω>5.2GHz

Scaling 5ules for a 6lab: aveguide 6tructure &omprising 1onlinear and 1egative, ndex 0aterials

We consider a Kerr-type nonlinear guiding layer surrounded by at least one medium made of a negative index material (NIM). Three different structures are investigated in this work. The first structure has a NIM cladding, the second has a NIM substrate, and the third has a NIM substrate and cladding. Three normalized parameters are used to study the dispersion characteristics of these waveguide structures. The dispersion curves are obtained and the effect of the NIM parameters on the guidance properties is presented. It is found that the dispersion characteristic of nonlinear waveguide structure with NIM cladding and dielectric substrate are similar to those for the same structure with NIM substrate and dielectric cladding. However, when both of them are NIMs new properties can be seen