Each of these particles — every quantum of light at a given wavelength — carried the same amount of energy, he argued, and so dispatched a single electron with the same energetic kick. (discovermagazine.com)
The «phase velocity» describes how fast waves of a given wavelength move, and the «group velocity» describes how fast the light conveys energy or information. (sciencemag.org)
CHESS is equipped with what's known as a spectrograph, which can parse out just how much of any given wavelength of light is present. (sciencedaily.com)