We could use a good way to machine very small things-- not nano scale but more on the order of 0.1" overall, with features down to ~ 0.0001" maybe. (For scale purposes, 1 micron is 0.00004")
optics for things like a 2:1 splitter
reflector for tethyx
It would be really cool to be able to machine lenses in some way where they'd have optically useful surface properties (smooth finishes, etc.)
A piece of this puzzle is probably vapor deposition and sputter coating.
This open access book looks like a great place to start learning about this.
-- BenDugan - 04 Jul 2013