He is a professor emeritus of physics at the University of California, Berkeley, known for his work on non-linear optics.
In the early years, Shen was probably best known for his work on self-focusing and filament propagation of laser beams in materials.
The molecular-beam photofragmentation translational spectroscopy that they developed has clarified much of the initial confusion concerning the dynamics of infrared multiphoton dissociation processes.
[2] In the 1980s and 1990s, Shen developed various nonlinear optics methods for the study of material surfaces and interfaces.
He has collaborated with Gabor Somorjai on the use of the technique of Sum Frequency Generation Spectroscopy to study catalyst surfaces.