Adaptive optics is a technology that can remove the blurring
effects of turbulence in the earth’s atmosphere, so that
telescopes on the ground can “see” as clearly as if they were in
space. I will describe the basic principles of adaptive optics,
and illustrate why lasers are needed to increase the fraction of
the sky where one can apply adaptive optics corrections. As one
example of astronomical observations which have benefitted
strongly from adaptive optics correction. I will describe our
recent detections of dual supermassive black holes in colliding
galaxies. I will conclude with a look forward to the adaptive
optics systems of the future.