Coupling nanoscale emitters via optical antennas enables comprehensive control of photon emission in terms of intensity, directivity and polarization. In this work we report highly directional emission of circularly polarized photons from quantum dots coupled to a spiral optical antenna. The structural chirality of the spiral antenna imprints spin state to the emitted photons. Experimental resu...

The auditory impression of sound sources is strongly influenced by the room, which, e.g., determines the apparent source width. What is more, typical sources are not omnidirectional, which also makes their orientation a strong influence. This influence, however, has only been investigated a little, although it can even change the perceived location of the source. To provide more insight, we per...

The DC motor is an important part of an equipment in many industrial applications requiring variable speed and load characteristics due to its ease of controllability. Nowadays, there are lots of good-quality motor speed controllers on the market. However, their costs are relatively high. A speed controller with both low cost and good performance will be highly marketable, especially for small ...

Cones show a differential sensitivity to light coming from different portions of the pupil, typically being most sensitive to light from the center of the pupil. We measured the directional properties of the cones across the central 6 deg of the retina, using an optical imaging technique. We find that the cones in the center of the fovea have the broadest tuning. The width of the angular tuning...

Directional couplers are critical components in photonic integrated circuits used in optical communication systems. The conventional directional couplers with laterally arranged waveguides can not achieve very short coupling lengths due to extreme sensitivity to fabrication variations and limitations to produce uniformly very narrow gap layers.1) Vertical directional couplers, however, can obta...

Non-contrast computed tomography (NCCT) remains a widely used imaging technique and plays an important role in the evaluation of patients with acute ischaemic stroke. However, the task of identifying the signs of acute ischaemia and quantifying areas of brain involvement on NCCT scan is not easy due to its subtle findings. The reliability of early ischemic sign detection can be improved with ex...

A novel ultra-short polarization beam splitter (PBS) based on a bent directional coupler is proposed by utilizing the evanescent coupling between two bent optical waveguides with different core widths. For the bent directional coupler, there is a significant phase-mismatch for TE polarization while the phase-matching condition is satisfied for TM polarization. Therefore, the TM polarized light ...

Anharmonic thermal effects on the electron momentum distribution of a lithium fluoride single crystal are experimentally measured through high-resolution Compton scattering and theoretically modeled with ab initio simulations, beyond the harmonic approximation to the lattice potential, explicitly accounting for thermal expansion. Directional Compton profiles are measured at two different temper...

Structural coloration produces some of the most brilliant colors in nature and has many applications. Motivated by the recently proposed transparent displays that are based on wavelength-selective scattering, here we consider the new problem of transparent structural color, where objects are transparent under omnidirectional broad-band illumination but scatter strongly with a directional narrow...

The directional tuning profiles of motor cortical cells are commonly described by a cosine tuning function with three adjustable parameters (Georgopoulos, A.P., Kalaska. J.F., Crutcher, M.D., Caminiti, R., Massey, J.T., 1982. On the relations between the direction of two-dimensional (2D) arm movements and cell discharge in primate motor cortex. J. Neurosci. 2, 1527-1537). In this study the vari...