Abstract: The photoelectric effect is fundamental in laser-matter interaction. Generally, students are taught by introducing the Einstein’s photoelectric-effect equation. In this paper, we propose to teach the photoelectric effect in a time-resolved perspective. According to the time-dependent perturbation theory, the electron may absorb random photons at any time, and the transitions at different moments interfere each other, resulting in the ultimate photoelectron within the expectation of Einstein’s photoelectric-effect equation. The similarity about the time-resolved photoelectric effect and Feynman path integral is analyzed. Students are suggested to conceive a strategy to observed the double-time-slit interference by using two laser pulses. 

Key words: photoelectric effect, time resolved, Young’s double-slit interference