Abstract:

Spectral line profile distortion, resulted from self-absorption of rubidium atoms in the rubidium spectral lamp bulb, is detrimental to the frequency stability of rubidium frequency standard. In this study, the hyperfine spectral profiles of rubidium lamps were studied with an F-P interferometer, and the influence of the type and pressure of buffer gas, lamp operating temperature and radio frequency-excitation power on self-absorption was examined. The results showed that the lamps filled with Ar gas or Kr gas showed serious self-absorption, while Xe-filled lamps had less self-absorption. Self-absorption could also be reduced by either sufficiently decreasing the operating temperature or increasing the pressure of buffer gas and rf-excitation power of the lamp.

Key words: rubidium atomic frequency standard, rubidium spectral lamp, self-absorption, hyperfine spectral profile