Talk:Rayleigh length

A citation is needed to support the definition of Rayleigh length as the distance required to reach double the beam cross-section. This is obviously true for a Gaussian beam, but I am not sure that it remains true when the concept of Rayleigh length is applied to beams that are not a pure TEM_0,0 Gaussian.--Srleffler (talk) 04:11, 4 February 2008 (UTC)

The lead says double cross section. The diagram appears to show ${\sqrt {2}}$ times cross section. --Kvng 16:38, 8 February 2011 (UTC)

The diagram shows that the radius increases by ${\sqrt {2}}$. The cross-sectional area doubles when the radius increases by ${\sqrt {2}}$.--Srleffler (talk) 01:15, 9 February 2011 (UTC)

Intensity or field

Does the condition on w0 apply to the intensity or the electric field? DiscountPundit (talk) 19:22, 16 March 2023 (UTC)

Either. w₀ is the radius at which the field amplitudes fall to 1/e of their axial values, or the radius where the intensity values fall to 1/e² of their axial values).--Srleffler (talk) 18:02, 18 March 2023 (UTC)