Four-wave mixing A weak optical signal (red) from a spacecraft transmitter can be amplified noise-free when it encounters two pump waves (blue and green) in a receiver on Earth. (Courtesy: Chalmers ...

The primary mechanisms leading to the production of single and entangled photon pairs revolve around established techniques such as parametric down-conversion, four-wave mixing, and stimulated Raman ...

Left and right Diagram showing how left circularly polarized (LCP) light is converted by the bifocal lens into separated beams of LCP light and right circularly polarized (RCP) light. (Courtesy: Fan ...