共查询到19条相似文献,搜索用时 218 毫秒
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运用数值模拟方法讨论了控制场的变化对M型五能级原子系统相对于探测场的吸收和色散等光学性质的影响.结果表明,改变控制场拉比频率时,系统的吸收和色散性质会发生规律性变化.在特定区域会呈现电磁感应透明窗口,其中透明窗口的数量与外加控制场数目成正比,而透明窗口宽度与拉比频率大小相关,拉比频率越大,透明窗口越平坦,当拉比频率减小,透明窗口变窄同时介质色散增强可获得慢光速光脉冲. 相似文献
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若干参数对瞬态电磁感应透明的影响 总被引:3,自引:0,他引:3
研究了原子梯形三能级系统的瞬态电磁感应透明特性,分析了系统各种参数,诸如瞬态作用时间、泵浦场和探测场的拉比频率、激光线宽及消相碰撞等因素对瞬态电磁感应透明的影响。结果表明:在不考虑激光线宽及消相碰撞时,探测场的吸收随时间在零吸收附近作类似于阻尼减幅振荡,系统可实现无反转放大;随着泵浦场的拉比频率的减小及上能级驰豫速率的增大,感应透明将减弱。在考虑到激光线宽及消相碰撞等非相干因素时,对于一定的瞬态作用时间,感应透明将随着探测场拉比频率的增大而减弱。 相似文献
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Taking the density-dependent near dipole-dipole (NDD) interaction into consideration, we theoretically investigate the response of nonlinear absorption and dispersion in optically dense media of three-level atoms driven by a single-mode probe laser. The influence of the NDD effects on the absorption and dispersion spectra of the probe field is predicted via numerical calculations. It is shown that the NDD effects reduce gradually to transient absorption and amplification with the increase of the strengths of the NDD interaction, but do not change the steady-state behavior.Due to the presence of the NDD effects, steady-state absorption spectra exhibit asymmetric double-peak structure and overall shifts when a continuous-wave (cw) probe field is applied. However, frequency dispersion spectra are insensitive to them near the zero detuning. 相似文献
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Several absorption and dispersion spectra of a probe and a coupling laser of different polarisations generating electromagnetically induced absorption in atomic caesium were measured and compared. In the case of at least one linearly polarised laser, electromagnetically induced absorption and absorption within transparency were observed for the probe and coupling laser, respectively. For laser beams of counter-rotating circular polarisation the coupling absorption spectra changed from absorption within transparency to transparency within transparency once the medium was saturated. However, the corresponding parametric dispersion spectra remained unchanged in structure. 相似文献
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Subluminal to superluminal light propagation in a V-type three-level atomic system interacting with squeezed vacuum 下载免费PDF全文
We study the light propagation properties in a V-type three-level atomic system interacting with two independent broadband squeezed baths. Using the graphic method, the dependences of the absorption and the dispersion of the system on the coupling field strength, the incoherent pumping field strength and the intensity of the squeezed vacuum are analysed. The result shows that the probe pulse propagation can be changed from subluminal to superluminal speed. 相似文献
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We theoretically investigate the spectral measurement errors that are apt to occur in continuous wave (CW) cavity ringdown (CRD) techniques suffering intracavity Doppler shifts. In the typical CW CRD scheme based on a cavity sweep operation for the resonant coupling of a probe laser into a ringdown cavity, the intracavity probe light detunes gradually over time, carrying time-dependent loss information of an absorption feature. Frequency-drifting ringdown signals are theoretically modelled and found to result in erroneous absorption spectra that exhibit the frequency shift of absorption profiles as well as linewidth broadening. PACS 42.62.Fi; 42.60.Da; 42.25.BS 相似文献
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计算了四能级Tripod-型原子系统中探针光极化率随其频率失谐量的变化曲线.结果表明,当触发光作用于该系统的一个共振跃迁能级时,可使探针光的吸收和色散在其电磁感应透明(Electromagnetically Induced Transparency,EIT)窗口(由耦合光产生)处发生显著变化.随着触发光Rabi频率的增加,探针光在EIT窗口的吸收显著降低,色散显著增加.这种由触发光引起的探针光极化率的变化对应着三阶Kerr非线性光学效应,这一效应在偏振量子相位门中有着潜在的应用价值. 相似文献
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We investigate self and cross-Kerr nonlinearity in a four level quantized graphene atomic medium. The absorption, dispersion, transmission and subluminal/superluminal behaviors of a probe light field are studied. An amplification of the probe light field is observed in the absorption spectrum. The normal and anomalous slope of dispersion is also investigated at the positive/negative absorption region. It is shown that Kerr nonlinearity invert and enhance the subluminal/superluminal behaviors of the pulse and self-Kerr effect is found to be more subluminal/superluminal as compared to cross-Kerr effect. The results show significant applications in information storage, self and cross phase modulation and lasing without inversion. 相似文献
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The properties of a five-level K-type system are investigated. With the controlling fields, the properties of the dispersion and absorption of the system are changed greatly. The system can produce anomalous dispersion regions with absorption and normal dispersion regions with absorption or transparency. Furthermore, the group velocity can be varied from subluminal to superluminal by varying the intensity of the controlling field and the probe detunings in principle. 相似文献
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We investigate the dispersion and the absorption properties of a weak field in a three-level Λ and V-type atomic system. We use just an incoherent pumping field to control the group velocity of a light pulse. The slope of dispersion is shown to be changed from positive to negative just by varying the intensity of the indirect incoherent pumping field. Gain-assisted superluminal light propagation appears in this system. No laser field is used in the pumping processes. 相似文献