Gaussian beam

In telecommunication, a gaussian beam is a beam of light whose electric field intensity distribution is gaussian.

Note: When such a beam is circular in cross section the intensity at distance r from the center, E (r ), is given by where E (0) is the electrical field strength at the beam center, i.e. , at r = 0; and w is the value of r at which the intensity is 1/e of its value on the axis.

Source: from Federal Standard 1037C