A new hybrid imaging detector is described that is being developed for the next generation adaptive optics (AO) wavefront sensors. The detector consists of proximity focused microchannel plates (MCPs) read out by pixelated CMOS application specific integrated circuit (ASIC) chips developed at CERN ("Medipix2"). Each Medipix2 pixel has an amplifier, lower and upper charge discriminators, and a 14-bit counter. The 256×256 array can be read out noiselessly (photon counting) in 286 μs. The Medipix2 is abutable on 3 sides to produce 512× (n *256) pixel devices. The readout can be electronically shuttered down to a temporal window of a few microseconds with an accuracy of 10 ns. Good quantum efficiencies can be achieved from the x-ray (open faced with opaque photocathodes) to the optical (sealed tube with semi-transparent GaAs photocathode).