Light-sound interconversion in optomechanical Dirac materials.

Analyzing the scattering and conversion process between photons and phonons coupled via radiation pressure in a circular quantum dot on a honeycomb array of optomechanical cells, we demonstrate the emergence of optomechanical Dirac physics. Specifically we prove the formation of polaritonic quasi-bound states inside the dot, and angle-dependent Klein tunneling of light and emission of sound, depending on the energy of the incident photon, the photon-phonon interaction strength, and the radius of the dot. We furthermore demonstrate that forward scattering of light or sound can almost switched off by an optically tuned Fano resonance; thereby the system may act as an optomechanical translator in a future photon-phonon based circuitry.

[Ultrasonographic determination of amniotic fluid--comparison of two methods].

A study was performed in order to find a suitable ultrasonographic method of determining amniotic fluid volumes. Volumes were measured in 398 gravidae with no fetal or maternal pathology. The Depot V method described by Chamberlain et al.