Willis E. Lamb

Anomalous fine structure of hydrogen and singly ionized helium

An account is given of theoretical and spectroscopic studies of the fine structure of the n=2 levels of atomic hydrogen and singly ionized helium, and of the work of Lamb, Retherford and Skinner in which microwave methods are used to establish deviations from the Dirac theory. A qualitative description of the theoretical explanation in terms of quantum electrodynamic level shifts is followed by comparison with observations.

Buildup of Laser Oscillations from Quantum Noise

Buildup of laser oscillation is expressed in terms of the probabilities p(n)(t) that there are n photons in the laser cavity. These probabilities obey a coupled set of difference-differential equations of motion. The method and results of numerical integration of these equations are given here for the initial condition that no photons exist (radiation field vacuum). Corresponding equations of motion for the moments of the photon distribution are derived, and their time dependences are given. A movie showing the time development of the p(n) from an initial vacuum is given on the corners of the November 1970 issue of Applied Optics and can be seen by flipping through the pages.