  Optical interferometry has been successful at achieving milliarcsecond
resolution on bright stars. Imaging performance can improve greatly by
increasing the number of baselines, which has motivated proposals to build
large (~ 100 m) optical interferometers with tens to hundreds of telescopes. It
is also desirable to adaptively correct atmospheric turbulence to obtain direct
phased images of astrophysical sources. When a natural guide star is not
available, we investigate the feasibility of using a modified laser-guide-star
technique that is suitable for large diluted apertures. The method consists of
using sub-sets of apertures to create an array of artificial stars in the
sodium layer and collecting back-scattered light with the same sub-apertures.
We present some numerical and laboratory simulations that quantify the
requirements and sensitivity of the technique.
