#PhysicsJournalClub
"Three-dimensional holographic imaging of incoherent objects through scattering media"
by Y. Baek, H. de Aguiar and @sylvaingigan
https://arxiv.org/abs/2502.01475
#optics #physics #imaging
As you daily experience anytime you look at anything, light scattering severely impairs your ability to image (mild scattering like mist makes things in a distance fuzzy, strong scattering like your own body makes it completely impossible to see what is happening inside or behind it). On one hand this is good, as it allows us to see where (e.g.) trees are so we don't bump into them. On the other hand there are a LOT of situations where you would really like to see what is going on behind a scattering medium (surely it would save a lot of exploratory surgeries).
The problem of imaging through a scattering medium is largely unsolvable in its most general form, but there are a lot of special cases where you can go surprisingly far, and people (me included) have spent a lot of time checking exactly how far.
In this paper the authors consider a set of small fluorescent objects behind a not-too-thick scattering medium, and look for a way to retrieve their 3D arrangement.
Problem: fluorescent emission means incoherent emission, so the phase information (which encodes a lot of information about position) is lost. Still, we can rely on the assumption that there is a finite (ideally not too large) amount of point emitters. Since each emitter is point-like, if we only measure the light that reaches us through the scattering medium at a single frequency (to be more realistic, a small bandwidth), we will see the incoherent sum of a speckle pattern per fluorescent emitter.
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Another image by request. @Sterling @charlesrkiss 
