Professor Wang's research focuses on biomedical imaging. In particular, his lab has developed photoacoustic imaging that allows peering noninvasively into biological tissues. Compared to conventional optical microscopy, his techniques have increased the penetration by nearly two orders of magnitude, breaking through the optical diffusion limit. The Wang lab has invented or discovered functional photoacoustic tomography, 3D photoacoustic microscopy, optical-resolution photoacoustic microscopy, photoacoustic Doppler effect, photoacoustic reporter gene imaging, microwave-induced thermoacoustic tomography, universal photoacoustic reconstruction algorithm, time-reversed ultrasonically encoded optical focusing, and compressed ultrafast photography (the world's fastest camera capable of 210 trillion frames per second). Combining rich optical contrast and scalable ultrasonic resolution, photoacoustic imaging is the only modality capable of providing multiscale high-resolution structural, functional, metabolic, and molecular imaging of organelles, cells, tissues, and organs, as well as small-animal organisms in vivo. Broad applications include early cancer detection, surgical guidance, and brain imaging. Professor Wang's Monte Carlo model of photon transport in scattering media is used worldwide as a standard tool.

His quantum research spans quantum entanglement, quantum imaging, and atomic physics. Entangled photons exhibit intrinsically nonclassical correlations that enable quantum imaging capabilities beyond those of classical optics, including sub-shot-noise performance and super-resolution beyond the diffraction limit via coincidence detection. Because photons ultimately originate from atomic and molecular transitions, he also investigates atomic physics at the classical–quantum interface. He recently found that the Bloch equation, traditionally regarded as purely classical, can yield the von Neumann equation and the Schrödinger equation. In addition, he developed a theory that more accurately models the multi-stage Stern–Gerlach experiment proposed by Heisenberg and Einstein than existing approaches.