Gaussian beam

Summary

A Gaussian beam is a light beam whose transverse intensity profile is a Gaussian function at every point along its axis. It is the simplest solution of the paraxial wave equation of finite power, and it models the output of most lasers. The beam has a narrowest place, the waist, and widens on both sides of it, slowly at first and then linearly with distance. Its width, wavefront curvature and phase are given by simple closed formulas in terms of the waist radius and the wavelength.