Efforts towards a low-temperature-sensitive physics package for vapor cell atomic clocks

Abstract

Abstract Strong environmental dependence is an intractable problem for vapor cell clocks, for which the high-temperature sensitivity of the physics package is considered one of the dominant reasons. In this paper, we report the design and realization of a low-temperature-sensitive physics package for vapor cell clocks. The physics package comprises three layers of magnetic shields, three layers of heating ovens, and the cavity-cell assembly. The cavity-cell assembly employs a compact magnetron-type cavity and a Rb vapor cell sealed with N2-Ar mixed buffer gas. The dependence of the clock frequency on temperature fluctuation is evaluated to be 2 × 10−11/°C. In pursuit of the stable temperature, a three-stage temperature regulator is implemented on the physics package. It adopts a combination of open and closed-loop control to address the problem of significant thermal coupling between the heating ovens. Under a laboratory environment, the measured Hadamard deviation of the temperature variation is 4 × 10−5 °C in 1 day of averaging.

Keywords

• Vapor cell atomic clock
• Physics package
• Temperature sensitivity