In this study, we investigate the coherent optical phenomena exhibited by a hybrid quantum-plasmonic system in Ξ configuration composed of four energy levels, featuring two closely spaced uppermost energy levels interacting with a weak probe field and a strong control field. The lower leg of Ξ system engages with the free-space vacuum, while the upper leg responds to interactions with surface plasmons. We reveal a significant transformation in the absorption and dispersion characteristics of this quantum system. This evolution is influenced by the interplay between quantum interference resulting from the presence of plasmonic nanostructures and the effects of incoherent pumping. In the absence of an incoherent pump field, we observe the emergence of multiple distinct absorption profiles, each containing optical transparency windows nestled amidst absorption spectral peaks. Introduction of an incoherent pump field leads to two well-defined symmetrical gain dips, each separated by a frequency corresponding to the dressed eigenstates of the system. This unique gain behavior persists whether or not population inversion occurs. We also show that these effects can be complemented with the existence of fast or slow light, expanding the range of optical phenomena that can be harnessed within this quantum system.

在这项研究中，我们研究了由四个能级组成的 Ξ 配置的混合量子等离子体系统所表现出的相干光学现象，其中两个紧密排列的最高能级与弱探测场和强控制场相互作用。 Ξ 系统的下腿与自由空间真空接合，而上腿则响应与表面等离子体激元的相互作用。我们揭示了该量子系统的吸收和色散特性的显着转变。这种演变受到等离子体纳米结构的存在引起的量子干涉与非相干泵浦效应之间相互作用的影响。在没有不相干泵浦场的情况下，我们观察到多个不同吸收轮廓的出现，每个吸收轮廓都包含位于吸收光谱峰之间的光学透明窗口。引入非相干泵浦场会导致两个明确定义的对称增益下降，每个增益下降都由与系统的修饰本征态相对应的频率分开。无论是否发生种群反转，这种独特的增益行为都会持续存在。我们还表明，这些效应可以与快光或慢光的存在相补充，从而扩大了该量子系统中可以利用的光学现象的范围。