Long ago I did semiconductor work for https://www.flatfrog.com/flatfrog-board https://www.flatfrog.com/flatfrog-board , which uses the beam principle combined w

Long ago I did semiconductor work for https://www.flatfrog.com/flatfrog-board https://www.flatfrog.com/flatfrog-board , which uses the beam principle combined with in-surface refraction, and I see they're still pretty expensive. You do get an awful lot of little DSPs around the edge for that price, though.