Rayleigh length (range)


In optics and especially laser science, the Rayleigh length or Rayleigh range is the distance along the propagation direction of a beam from the waist to the place where the area of the cross section is doubled.
Rayleigh length is particularly important when beams are modeled as Gaussian beams. For a Gaussian beam propagating in free space along the z-axis, the Rayleigh length is depended on the wavelength and the radial size of the beam at its narrowest point.

Related formulas


zRRayleigh length (m)
w0The beam waist (m)
λThe wavelength (m)