Paper 5.10: R. Yen, P. Liu, M. Dagenais and N. Bloembergen, “Incident angle and polarization dependence of four-photon photo-emission from tungsten,” Optics Comm. 31, 334–339, 1979.

This is a continuation of the work started in the preceding note. It was possible to separate volume and surface contributions of a multiphoton photoelectric emission process.

Pao-lo Liu was a graduate student who is now a professor of electrical engineering at the State University of New York in Buffalo. Richard Yen was a graduate student who really preferred to go into business. With my encouragement, he finished his Ph.D. degree to comply with the wishes of his parents. He was a competent scientist, but he chose to become a successful entrepreneur in electronics technology.