  Ultrasound-modulated optical tomography (UOT) is a technique that images
optical contrast deep inside scattering media. Heterodyne holography is a
promising tool able to detect the UOT tagged photons with high efficiency. In
this work, we describe theoretically the detection of the tagged photon in
heterodyne holography based UOT, show how to filter the untagged photon
discuss, and discuss the effect of speckle decorrelation. We show that optimal
detection sensitivity can obtain, if the frame exposure time is of the order of
the decorrelation time.
