非旋波近似下频率变化的光场对原子布居反转的调控

利用相干态正交化展开方法,在非旋波近似下研究了原子的布居反转随时间的演化情况.数值计算的结果表明了,场频以及耦合强度不随时间变化时,布居反转的周期随着平均光子数的增加而增大,虚光子效应引起的快速振荡随耦合强度的增大而逐渐增大.当光场随时间做正弦调制时,光场的振幅α和角频率β对布居反转的演化都会产生很大影响.光场随时间做方波形式变化,会导致原子布居反转出现新的塌缩回复现象.无论是正弦调制还是方波调制,都会对由虚光子效应产生的小锯齿状的振荡产生影响.关键词：相干态正交化展开非旋波近似原子布居数反转

Influence of the field with varying frequency modulation on atomic population inversion in non-ratating-wave approximation

By the method of coherent-state orthogonalization expansion, the evolution of atomic population inversion is investigated in the non-rotating-wave approximation. The numerical results indicate that, when field frequency and coupling do not change with time, the collapse-revival period of population inversion increases with the mean photon number of the field increasing, and the quick oscillation due to virtual photon process increases with couplings strengthening. When the frequency changes with time in the sine form, amplitude α and angle frequency β of the field both have a great influence on atomic population inversion. The sudden jumping of the field frequency can lead to some new collapses and rebibals in the evolution of atomic population inversion. Both of the field frequency forms can have an influence on quick oscillation due to virtual photon process.