Cesium atoms oscillate at microwave frequencies, and are usually paired with a vibrating quartz crystal to keep time.

铯原子以微波频率振荡，通常与振动的石英晶体配对以计时。

Caesium beam frequency standard, external oscillator generates a microwave frequency and induce those atoms to go into resonance, oscillating at that frequency for equal flux of atoms in the two hyperfine states.

铯束频率标准，外部振荡器产生微波频率并诱导这些原子进入共振，在该频率下振荡，从而获得两个超精细态中原子的相等通量。

The technology is getting to the point now where that microwave frequency isn't precise enough for the applications that require precise time, so we are now working to develop optical frequency standards.

这项技术现在已经到了微波频率对于需要精确时间的应用来说不够精确的地步，所以我们现在正在努力开发光学频率标准。