Indestructible light waves travel through opaque material as if it isn’t there

I really hate when the press releases don't actually reflect the science in the paper. In this case there are no indestructible light waves and there is no opaque material. There is simply a wavefront which passes through free space (air) and through a scattering medium (what you would probably call a translucent material) such that the relative intensity of the two images produced are the same. The phase of the light is not the same and neither is the intensity because some is absorbed and reflected by the scattering medium.

> To do this, the researchers first had to characterize the scattering medium precisely. At Utrecht University, they shone light through a layer of zinc oxide nanopowder deposited on a glass slide. They then used a detector on the other side to measure the light and analyse how it had been scattered by the powder. Once this has been done, Rotter explains, you can calculate “what kind of wave would be transmitted through this medium in the same way as through fresh space”.

So it's not just any opaque material (and it's not even "opaque", really), and it's not just any waveform. The headline is pretty darn baity.

Nonetheless, the science here is pretty cool. I could have imagined taking a scattering medium and a desired final waveform and computing the initial waveform that would produce the final waveform, but this seems to be saying that there exist waveforms that are essentially fixed points of the transform induced by the scattering medium. I wonder whether how exact that is -- whether the waveform really is identical, or whether any differences are simply hidden below the threshold of measurement sensitivity.

Opaque / oʊˈpeɪk /, adj. not transparent or translucent; impenetrable to light; not allowing light to pass through.

I feel like maybe you need to be more precise in what you mean by 'opaque' before you can make a claim like this...

Looks like it works for thin scattering layers, but you have to customize the light pattern for that specific sample and that specific angle and distance. So it’s not something that will allow a flashlight to shine through a wall.

Arxiv link to the paper https://arxiv.org/abs/2010.01075

"Modelling scattering media with a thickness of 1-9μm" would be a better title. It's something, but the layer is so thin that the title looks like a joke.

OK dumb question but if x-rays are a form of light and we use them to see into the body through an opaque material (flesh), how is this news?

One step closer to the Tricorder.