Gaussian beam (Beam width or spot size)


In optics, a Gaussian beam is a beam of electromagnetic radiation whose transverse electric field and intensity (irradiance) distributions are well approximated by Gaussian functions. For a Gaussian beam propagating in free space, the spot size (radius) will be at a minimum value at one place along the beam axis, known as the beam waist. For a beam of wavelength λ at a distance z along the beam from the beam waist, where the origin of the z-axis is defined, the variation of the spot size can be calculated by the waist size and the Rayleigh range.

Related formulas


wzThe spot size (m)
w0The waist size (m)
zThe distance along the beam from the beam waist (m)
zRThe Rayleigh range (m)