Lamp Stabilization Using Ion Waves: Smart-Clock Technology to Eliminate Light-Shift Variations

Abstract

Stabilization of the radiowave power driving an RF-discharge lamp has important implications for the long-term stability of atomic clocks. Here, the authors demonstrate a technique in which the lamp's plasma acts as a probe of radiowave power, and provides a correction signal for active rf-power control. The technique takes advantage of the resonant nature of forced ion waves in the plasma and their observation in the lamp's optical emission. Following a discussion of lamp stabilization using ion waves, we consider the question of how the induced oscillations might affect clock performance via the light shift. We argue that the amplitude of the oscillations is small enough so that they would at most lead to frequency instability at the 10-15 level