Experimentally, a light pulse propagating through the atomic vapor cell has its peak reaching the exit side before entering it, resulting in a negative transit time, and negative group velocity.

研究发现，当光脉冲通过一个原子气室时，在进入前其峰即到达出口处，造成负渡越时间和负群速。

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Experimentally, a light pulse propagating through the atomic vapor cell has its peak reaching the exit side before entering it, resulting in a negative transit time, and negative group velocity.

研究发现，当光脉冲通过一个原子气室时，在进入前其峰即到达出口处，造成负渡越时间和负群速。

youdao