The transmission of light through a disordered medium is described in microscopic detail by a high-dimensional matrix. Researchers have now measured this transmission matrix directly, providing a new approach to control light propagation.
Magnetic switching is typically a continuous process, where a field pulse rotates a magnet from up to down, but it is now possible to do this faster — and with all-optical methods — by first quenching the magnetization to zero and then repolarizing it in the opposite direction.
This design of atomic quantum memory tells us when a pulse of light has been successfully stored and then proceeds to retrieve it without significantly affecting its polarization. The exquisite operation provides a new capability for quantum information networks.
A proposal for obtaining optical resolution better than the classical limit by means of spatially entangled quantum states of light opens a new frontier in the fields of quantum optical imaging, metrology, and sensing.
The blurring effects of diffraction pose an obstacle to transmitting an image with all-optical technology. A method to reduce diffraction that takes advantage of the thermal motion of atoms could prove a way to keep images sharp.