European scientists have demonstrated a prototype of a system that reconstructs the "structure" of a diffuse barrier and displays an image on the other side of it.
A diffuse medium, be it a cloud or a translucent glass, is filled with a "suspension" of randomly distributed particles. The light passing through it is scattered by these particles, so it is so difficult to see anything through the fog. However, scientists from Austria and the Netherlands have demonstrated a prototype of a system that allows images to be transmitted through such diffuse obstacles. An article by Stefan Rotter and his colleagues was published in the journal Nature Photonics.
The fact is that most photons are scattered on particles of a diffuse medium, but not all. Some of them - "ballistic" - manage to slip through without colliding with anything along the way and without changing their trajectory. Theoretically, by collecting a sufficient number of observations of ballistic photons, it is possible to reconstruct the original image.
However, scientists have now used them to reconstruct the distribution of particles in the barrier itself. They took glass with zinc oxide spheres introduced into it and, at the first stage, "enlightened" so that the ballistic photons caught by the detector indicate in which areas and along what trajectories they are able to penetrate.
Having thus determined the "structure" of the obstacle, the authors of the study were able to illuminate it with a new beam of rays, which safely passed through the dull glass and on the other side formed an image - the Big Dipper's bucket.