I have not yet seen this very intriguing development mentioned on Cloudy Nights, at least not in its Refractor forum. My apologies if I am duplicating an earlier post about this.
If I understand it correctly, implementation of the concept would permit construction of long focal-length refractors in (very) short tubes. Among other things, that could greatly simplify design of mounts and make such optics again available to those with aging muscles and backs.
The original publication is in a highly respected, peer-reviewed journal, Nature Communications.
Barrel-Eliminating Optical Element Enables Massive Zoom in Tiny Form Factor
"OTTAWA, Ontario, June 10, 2021 — A novel optical element will one day enable composite lenses and telescopes in a form factor small enough to fit in a pocket. The device, developed by Orad Reshef and Jeff Lundeen of the University of Ottawa, is called a spaceplate. Its function, say its developers, is to mimic the empty space needed to focus an image — meaning one day photographers will be able to take pictures of faraway subjects without lugging around a long-barrel telephoto lens."
“A spaceplate is an optical element that propagates light for a distance that exceeds its thickness,” Reshef and Lundeen told Photonics Media in an email correspondence. “From the perspective of a beam of light, after traveling through a spaceplate, it acts as if it has traveled through a thicker region of space.”
An optic to replace space and its application towards ultra-thin imaging systems
Orad Reshef, Michael P. DelMastro, Katherine K. M. Bearne, Ali H. Alhulaymi, Lambert Giner, Robert W. Boyd & Jeff S. Lundeen
Nature Communications volume 12, Article number: 3512 (2021)