量子光学学报
量子光學學報
양자광학학보
ACTA SINICA QUANTUM OPTICA
2014年
2期
110-118
,共9页
电磁感应透明%瞬态响应时间%微扰理论
電磁感應透明%瞬態響應時間%微擾理論
전자감응투명%순태향응시간%미우이론
electromagetically induced transparency%transient response time%Perturbation theory
详细研究了Λ型三能级原子系统中电磁感应透明的瞬态过程。我们从理论上分析了系统中各参数(例如失谐、原子能级衰减率、探测场和耦合场强度)对瞬态响应时间的影响,并且通过对密度矩阵演化方程的数值求解,分析了相关密度矩阵元尤其是与吸收和色散相关的矩阵元ρab的瞬态行为。结果发现:在满足双光子共振条件Δ=Δμ的情况下,瞬态响应时间与能级衰减速率以及探测场和原子跃迁的失谐有直接关系;随着失谐的增大,响应时间也相应延长,同时,瞬态响应时间也随着衰减率γ的增大而缩短。而探测场和耦合场的强度变化并未对响应时间造成影响。此外,很多文献都指出,常用的微扰近似稳态解只适用于探测场强度远小于耦合场强度的情况,而本文则通过对比数值解的稳定值和微扰近似稳态解的差异,给出了其适用的确切范围:即应满足犘E/≤0.1Ωμ。
詳細研究瞭Λ型三能級原子繫統中電磁感應透明的瞬態過程。我們從理論上分析瞭繫統中各參數(例如失諧、原子能級衰減率、探測場和耦閤場彊度)對瞬態響應時間的影響,併且通過對密度矩陣縯化方程的數值求解,分析瞭相關密度矩陣元尤其是與吸收和色散相關的矩陣元ρab的瞬態行為。結果髮現:在滿足雙光子共振條件Δ=Δμ的情況下,瞬態響應時間與能級衰減速率以及探測場和原子躍遷的失諧有直接關繫;隨著失諧的增大,響應時間也相應延長,同時,瞬態響應時間也隨著衰減率γ的增大而縮短。而探測場和耦閤場的彊度變化併未對響應時間造成影響。此外,很多文獻都指齣,常用的微擾近似穩態解隻適用于探測場彊度遠小于耦閤場彊度的情況,而本文則通過對比數值解的穩定值和微擾近似穩態解的差異,給齣瞭其適用的確切範圍:即應滿足犘E/≤0.1Ωμ。
상세연구료Λ형삼능급원자계통중전자감응투명적순태과정。아문종이론상분석료계통중각삼수(례여실해、원자능급쇠감솔、탐측장화우합장강도)대순태향응시간적영향,병차통과대밀도구진연화방정적수치구해,분석료상관밀도구진원우기시여흡수화색산상관적구진원ρab적순태행위。결과발현:재만족쌍광자공진조건Δ=Δμ적정황하,순태향응시간여능급쇠감속솔이급탐측장화원자약천적실해유직접관계;수착실해적증대,향응시간야상응연장,동시,순태향응시간야수착쇠감솔γ적증대이축단。이탐측장화우합장적강도변화병미대향응시간조성영향。차외,흔다문헌도지출,상용적미우근사은태해지괄용우탐측장강도원소우우합장강도적정황,이본문칙통과대비수치해적은정치화미우근사은태해적차이,급출료기괄용적학절범위:즉응만족마E/≤0.1Ωμ。
In this paper the transient behavior of electromagnetically induced transparency in three-levelΛ-type atomic systems was investigated in detail. We analyzed theoretically the influence of the system parameters (i.e.detuning,decay rate,strength of external field)on the transient responsing time and the transient behavior of corresponding density matrix element especially forρab via exact numerical calculation. The results show that the responsing time has a direct relation to the decay rate and the detuning between the driven and probe fields.Choosing a suitable environment of larger decay rate can significantly shorten the responsing time.Meanwhile,the transient process should be prolonged when adopted detuning probe field and the responsing time is insensitive to the strength of driven and probe fields.The limitation on the relative strength of probe field to the driven field,which is suitable for the usual approximation steady-state theory,was also discussed.And we find the limit intensity of the probe field in the approximate solutions isPE/≤0.1Ωμ.