Just hangs there in the air? No enclosure to block direct sunlight and allow the red/green dot to be actually seen by your eye during daytime?

Suspicious Cat (shows photo of cat squinting and giving a side-eye look of doubt) remains suspicious…

Well, I came back to read it. Very interesting, and thanks for the links.

never mind, the post in moderation finally appeared. Its like having a discussion after the discussion is over and everyone left.

I replied to your post, unfortunately it went to moderation (links I guess) so it will hopefully show up when someone at SNW decides to look.

I said the technology for such an RDS has been available, not an actual RDS. Actually, the method and technology was created in 2014 at the Los Alamos National Laboratory for projecting a laser dot suspended in 3D space. The broad term applied for the method is ‘volumetric images’, the method is also called ‘Photophoretic optical trapping’

Its a physics thing, basically a laser beam traps a ‘particle’ (or ‘particles’) in the air (and despite the air looking ‘clear’ there are always ‘particles’ in the air that can be trapped. No, it does not need to be a dust particle even though no matter how much you clean the air there are always some microscopic dust particles around any object even in outer space. But anyway, by trapping this ‘particle with the laser beam the particle movement can be manipulated and that movement can be used to produce a pattern (e.g. for our purposes a dot or reticle) and the resulting ‘volumetric image’ (in our case – reticle) appears suspended in air and occupies 3D space basically like, for example, your hand does.

We’ve played with this idea in the lab and actually created a sight that we put on a Glock, it was a simple cross hair type reticle. Its a little ‘experiment’ clunky size wise as its an experimental thing anyway – but it works.

Here is a video that explains the basic idea (the video was done 6 years ago – but the technology to do it has been available to the commercial market for the last 10 years in different ‘undeveloped for purpose’ forms. But it is in use…Ya got a CAT scan in the hospital with a system made in the last 10 years, then this method is in that machine and being used – its just presented more traditionally with screens and on film or video as the images you see in 2D space). Anyway, the video > https://www.youtube.com/watch?v=YRZMdQOMPNQ

And for example > https://phys.org/news/2021-05-hologram-experts-real-life-images-air.html

WRT “an RDS that doesn’t need an enclosure,” citation please?

It does lack ‘innovation’ in many areas. Things that could have already been in the gun market aren’t because manufacturers are more into ‘bling’ and ‘wash rinse repeat, but change a dimple or color here and there’. For cripes sake’s, ‘how many FDE color shades can ya sell on the same hand guard series that wasn’t that great to begin with’ seems to just about sum it up.

For example; For 10 years the technology has been available to produce an RDS that doesn’t need an enclosure as it projects the dot/reticle above the pistol/rifle and its just there in the air. Imagine not having to specifically order a holster that’s cut for an RDS on the pistol, imagine a rifle RDS optic that ya don’t need to be concerned about getting the glass dirty or broken, imagine an RDS where your astigmatism didn’t matter and the dot was crisp and clear for anyone, imagine that bight light washout didn’t happen to the dot. One manufacturer had an opportunity to produce such a sight but turned down a chance to do so in favor of marketing eventually another rendition of their older M21 with their newest the M22 in an enclosure that follows the same ‘gotta have a big honkin hunk of plastic/alumimum material on top of your gun’ trope so many in the RDS optics market follow. And speaking of RDS optics, someone needs to explain to these manufacturers what the word ‘micro’ means because apparently to some of them it means ‘undefined big’.