Interesting. You could do this parallel rays effect with a lot of lower power leds and microlenses too? Could work with air cooling then (more surface area).

Would be nice to find somewhere that sells these lenses in bulk, from a quick search they seem to be quite expensive.

https://www.ledil.com/search/?families%5B%5D=Virpi&q= https://www.polymer-optics.co.uk/products-developments/led-o...

Found these. Main use is horticultural?

I think the second link with the collimating lenses is more what's needed. I was just looking at another page and saw that you can also buy collimating reflectors which might be cheaper than lenses. I wonder if that's something you could 3D print and then coat with something to make it reflective. It'd probably be better to build a tool to punch them out of stainless steel sheet metal and then polish them to a mirror finish.

They are already working on it: https://www.iter.org/ ;)

Fitting that in my room would be an issue though.

I have been seeing a lot of ads for "sunset projecting lamps" since I have watched this video.

https://www.today.com/shop/sunset-projection-lamps-t211085

I am not sure if they operate on the exact same science but they do seem somewhat similar.