Two-Photon Precision Spectroscopy of the 1S-2S Transition of Atomic Hydrogen

Abstract

Hydrogen, the simplest of the stable atoms, provides unique opportunities for critical confrontations of spectroscopic experiment and quantum electrodynamic theory. Recent advances in the generation, stabilization, and measurement of optical frequencies are extending radiofrequency resolution and accuracy into the ultraviolet spectral region. Precise measurements and comparisons of the optical frequencies of sharp hydrogen two-photon transitions are yielding new values of fundamental constants, and they are permitting stringent new tests of basic physics laws.