A novel system that continuously visualizes and analyzes respiratory sounds to promptly evaluate upper airway abnormalities: a pilot study.

Although respiratory sounds are useful indicators for evaluating abnormalities of the upper airway and lungs, the accuracy of their evaluation may be limited. The continuous evaluation and visualization of respiratory sounds has so far been impossible. To resolve these problems, we developed a novel continuous visualization system for assessing respiratory sounds.

Trapping waves with terahertz metamaterial absorber based on isotropic Mie resonators.

Quasi-monodisperse dielectric particles organized in a periodic hexagonal network on an aluminum surface are exploited numerically and experimentally as a single-layered near-perfect absorber in the terahertz regime. Of particular interest are titanium dioxide (TiO(2)) microspheres because of their large dielectric permittivity and isotropic shape leading to Mie resonances with insensitive polarization. Absorption higher than 80% at normal incidence covering two distinct ranges of frequencies is demonstrated experimentally.

Ultrafast optical control of group delay of narrow-band terahertz waves.

We experimentally demonstrate control over the group delay of narrow-band (quasi continuous wave) terahertz (THz) pulses with constant amplitude based on optical switching of a metasurface characteristic. The near-field coupling between resonant modes of a complementary split ring resonator pair and a rectangular slit show an electromagnetically induced transparency-like (EIT-like) spectral shape in the reflection spectrum of a metasurface. This coupling induces group delay of a narrow-band THz pulse around the resonant frequency of the EIT-like spectrum.