My favourites are the liquid crystal lenses. Essentially they are micron scale Fresnel lenses controlled by electric field. No moving parts, very thin, ideal for something like a camera module.
I'm surprised that nobody managed to commercialise it in that niche yet.
Do you have a link for that? They have used holographic optical elements to make shorter SLR lenses, although I don't think the image quality was excellent, but if they went to the trouble it must have been fairly good.
I'm surprised that nobody managed to commercialise it in that niche yet.