Highly Confined and Switchable Mid-Infrared Surface Phonon Polariton Resonances of Planar Circular Cavities with a Phase Change Material.

Mid-infrared (MIR) photonics demands highly confined optical fields to obtain efficient interaction between long-wavelength light and nanomaterials. Surface polaritons excited on polar semiconductor and metallic material interfaces exhibit near-fields localized on subwavelength scales. However, realizing a stronger field concentration in a cavity with a high quality ( Q) factor and a small mode volume is still challenging in the MIR region.

Exploring the detection limits of infrared near-field microscopy regarding small buried structures and pushing them by exploiting superlens-related effects.

We present a study on subsurface imaging with an infrared scattering-type scanning near-field optical microscope (s-SNOM). The depth-limitation for the visibility of gold nanoparticles with a diameter of 50 nm under SiN is determined to about 50 nm. We first investigate spot size and signal strength concerning their particle-size dependence for a dielectric cover layer with positive permittivity.

Visual search as a tool for a quick and reliable assessment of cognitive functions in patients with multiple sclerosis.

Background: Despite the high frequency of cognitive impairment in multiple sclerosis, its assessment has not gained entrance into clinical routine yet, due to lack of time-saving and suitable tests for patients with multiple sclerosis.

Objective: The aim of the study was to compare the paradigm of visual search with neuropsychological standard tests, in order to identify the test that discriminates best between patients with multiple sclerosis and healthy individuals concerning cognitive functions, without being susceptible to practice effects.

Methods: Patients with relapsing remitting multiple sclerosis (n = 38) and age-and gender-matched healthy individuals (n = 40) were tested with common neuropsychological tests and a computer-based visual search task, whereby a target stimulus has to be detected amongst distracting stimuli on a touch screen.