This feels like lazy reporting. One beam isn't blocking the other, it's inducing a localized nonlinear process in a material which then absorbs the crossing beam. This isn't a novel process.
It's like me saying if I close a door I'm casting a shadow, sure, I caused it, but it's not my shadow.
I was about to say the same thing... unless they can do this in vacuum, it's a curiosity, but not something novel.
Now do it without moving the door. That's what makes this interesting. It uses the crystal, but it's not changing the crystal.
Source publication (3 points, 3 days ago, 3 comments) https://news.ycombinator.com/item?id=42139019
Maybe this is wishful thinking but could something like this be used to make star wars style holograms? Strategically placed laser shadows to block light sounds like a useful tool in that direction.
We have holograms that are in 'open' space. The problem is they aren't particularly fast, safe, or interestingly- quiet.
The ones I know of converge multiple beams at a point; this results in a Bloom (https://en.m.wikipedia.org/wiki/Thermal_blooming). Not sure how they aim the beams. (Voice coil and mirrors, digital mirror device aka DLP. Both valid options with pros and cons)
Exploits nonlinear optical interactions in a medium (ruby) to cause one beam to cast a shadow from another beam.
Right. Materials with nonlinear optical properties make optical logic possible. Here's an overview of that.[1]
Cross-gain modulation (XGM)
XGM has been investigated extensively to design optical logic gates with SOA. It is assumed that there are two input light beams for each SOA. One is the probe light and the other is the much stronger pump light. The probe light cannot pass through the SOA when the pump light saturates it. The probe light can go through the SOA when the pump light is absent.
[1] https://www.oejournal.org/article/doi/10.29026/oes.2022.2200...
Link to the paper in Optica, "Shadow of a laser beam"
https://opg.optica.org/optica/fulltext.cfm?uri=optica-11-11-...
So slapdash Unity asset store video games were right all along!
Never bet against Unity
Interesting, Initially I thought it was a laser-laser interaction happening in vacuum.
You can make logical gates from this, right?