五能级87Rb原子系统中相干诱导的可调谐三光子带隙

研究了一个由两个同向驻波场和一个微波场相干驱动的五能级87 Rb原子系统,并在探测场共振频率处实现了可调谐三光子带隙。利用激光场与多能级原子系综相互作用的密度矩阵方程,结合光脉冲在具有空间周期性介质中的相干传输矩阵理论,推导出了描述相干原子系统稳态条件下的反射谱和透射谱。由数值模拟发现,通过改变驱动场的失谐和拉比频率可以动力学地调控光子带隙的位置和宽度,而且这种相干诱导三光子带隙能够同时操控三个不同中心频率光脉冲的传播。

Tunable Triple Photonic Band-Gaps Based on Coherent Induction in a Five-Level 87Rb Atomic System

A five-level 87Rb atomic system which is coherently driven by two standing-wave fields and a microwave field is investigated, and tunable triple photonic band-gaps at different resonance frequencies are obtained. The density-matrix equations are used to describe the interaction between fields and multi-level atoms, and the transfer-matrix method is used to describe the propagation of light in periodic media. The reflection spectra and transmission spectra of the coherent atomic system are deduced in the steady condition. The numerical simulation show that the positions and widths of the photonic band-gaps can be controlled by the detuning of the coherent fields and the Rabi frequency of the microwave field, and the type of triple photonic band-gaps can be applied to simultaneously manipulate the propagation of light pulses with three different central frequencies.