When a beam of light passes through a cloud of atoms, photons (particles of light) sometimes appear to spend a negative amount of time there, with light seeming to exit the cloud before it even enters ...

Everyone is familiar with the light dome that shows from afar where cities are brightly lit at night. Artificial light that is scattered in the atmosphere and brightens the night sky can have an ...

Researchers from Skoltech and the Shanghai Institute of Optics and Fine Mechanics have developed an approach that helps optimize the parameters of a laser-plasma source of attosecond pulses—ultrashort ...