Hi I am reading about spatial hole burning in the litterature, and I have come across two different explanations. I can't quite see how they relate to eachother. Here they are: 1) In this explanation one uses the fact that in a linear cavity the optical field is a superposition of two counter-propagating waves such that they produce a standing wave in the medium. This will deplete the gain in all the nodes of the standing wave pattern. 2) In this explanation one simply says that e.g. TEM00 will saturate the gain in the medium in a TEM00-pattern. As far as I can tell, these two explanations are not identical. Intuitively I would say the second one is the one that makes most sense, but the first one is mentioned in most books. Can someone shed some light on this matter? Any help is appreciated. Best, Niles.