Photo-acoustic and Thermo-acoustic tomography are hybrid medical imaging modalities where optical waves or electromagnetic waves and ultrasound waves are coupled. The propagation of ultrasound waves is typically modeled as an inverse source problem for the acoustic wave equation. In this talk we will discuss the inverse source problem in an inhomogeneous medium where the wave speed is variable. Two types of measurement are to be considered: one from pointwise detectors and the other from large planar detectors. We prove uniqueness and stability on the recovery of the source, and give reconstruction procedures for the source or its singularities. This is based on joint work with Plamen Stefanov.

Yang Yang received his Ph.D. in 2014 from University of Washington under Prof. Gunther Uhlmann, and his B.S. in 2009 from Zhejiang University in China. He was a Golomb Visiting Assistant Professor at Purdue University  from 2014-2017 and he is now an assistant professor in Michigan State University. His research focuses on inverse problems arising in medical imaging and geophysical imaging with connections to mathematical physics and relativity theory.