Laser cooling to create a miniature atomic clock

Kurt Gibble

王秀梅 Wang Xiumei, Danyang Wang, Yifei Wang +8 more

SummaryDiffuse laser cooling provides a compact cold atom system for quantum precision measurement processes, especially for the integrating sphere cold atom clock. However, the laser cooling system of current integrating sphere cold atom clock is bulky and complex, which is not conductive to the miniaturization of cold atom clock. In order to make a less complex diffuse laser cooling system, we adopt the scheme to combine the fiber mirrors and the diffuse laser cooling technique. The incident laser beams are reflected by the fiber mirrors and teflon, and the atoms can be successfully cooled and detected in the miniaturized zone. The preparation of fiber mirrors and the realization of diffuse laser cooling system with a simple optical system can lay a solid foundation for further miniaturization of the overall system of integrating sphere cold atom clock in the future.

Steven R. Jefferts

David R. Scherer, Robert Lutwak, Mark J. Mescher +8 more

Atomic clocks play a crucial role in timekeeping, communications, and navigation systems. Recent efforts enabled by heterogeneous MEMS integration have led to the commercial introduction of Chip-Scale Atomic Clocks (CSAC) with a volume of 16 cm3, power consumption of 120 mW, and instability (Allan Deviation) of σ(τ = 1 sec) < 2e-10. In order to reduce the temperature sensitivity of next-generation CSACs for timing applications, the interaction of atoms with the environment must be minimized, which can be accomplished in an architecture based on trapped, laser-cooled atoms. In this paper, we present results describing the development of a miniature cold-atom apparatus for operation as a frequency standard. Our architecture is based on laser-cooling a sample of neutral atoms in a Magneto-Optical Trap (MOT) using a conical retro-reflector in a miniature vacuum chamber. Trapping the atoms in vacuum and performing microwave interrogation in the dark reduces the temperature sensitivity compared to vapor-cell CSACs. We present details of the component development associated with the laser systems, opto-electronics, and vacuum package for miniature cold-atom technology. Finally, we conclude by characterizing the optimum alkali background pressure for such a cold-atom frequency standard.

Xiaochi Liu, Eugene N. Ivanov, Valeriy I. Yudin +2 more

Atomic clocks based on coherent population trapping (CPT) are of great interest for portable applications, due to their high performance, low power requirements, and potential for miniaturization. Slow frequency drift, however, limits their holdover ability on long time scales. This study reports a CPT clock that minimizes long-term drift, with a fractional frequency stability of $3\ifmmode\times\else\texttimes\fi{}{10}^{-13}$ over the span of an hour---ten times as good as previous CPT clocks. After successful shrinking of the laser-cooling apparatus, this clock could see commercial use, as the atoms fall just a few millimeters during a typical probe period.

William D. Phillips, John V. Prodan, Harold J. Metcalf