光速减慢

Light Speed Reduction

激光技术的发展为极限光速的测量提供了有效工具。主要介绍了与光速减慢有关的非线性光学知识和光速减慢的实验原理及方法。光速减慢实验中用到的低温 Na原子气在探测激光和耦合激光的共同作用下处于量子相干态——一种非线性极化状态 ,由于电磁感应透明效应 (EIT) ,探测光可以使介质的折射率改变并能透过 Na原子气 ,使光速减慢的测量变为现实。

The nonlinear optics related with light speed reduction and experimental method of light speed reduction are introduced.In the experiment, Na atom gas was on a quantum coherent state at nK temperature, when it was excited by probing laser and coupling laser. For electro-magnetically induced transparency (EIT), the probing laser canchange the medium susceptibility and transmit the atomic gas so that the measurement of light speed reduction is realized.