Yes, such a holographic lens is possible but it has extreme
limitations, notable it would work only at the wavelength at which the
original hologram was made. I also suspect it would have odd
aberations (other than chromatic). Such a lens would be diffractive
rather than refractive which is what may be confusing some people about
this possibility.
Theoretically, a Fresnel zone plate could be substituted for a lens but
such would be difficult to fabricate.

DBO

wrote:
You must be psychic! I suggested this idea a while ago.
I imagined a laser producing a large reflecting spherical surface in
a
cloud of reflective particles to act as a telescope primary.
The responses were't very positive last time round either. grin

Chris.B