Input-output theory of cavities in the ultrastrong coupling regime: The case of time-independent cavity parameters
Input-output theory of cavities in the ultrastrong coupling regime: The case of time-independent cavity parameters
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DOI：
10.1103/physreva.74.033811
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发表时间：
2006-09-01
影响因子：
2.9
通讯作者：
Carusotto, Iacopo
中科院分区：
文献类型：
--
作者：
Ciuti, Cristiano;Carusotto, Iacopo
我们给出了超强光-物质耦合光腔耗散动力学的全量子理论，其中真空拉比频率是有源电子跃迁频率的重要组成部分，光-物质耦合的反共振项起着重要作用。特别是，我们的模型可以应用于嵌入微腔的掺杂半导体量子阱中的子带间跃迁。通过输入输出形式的量子朗之万方程，考虑了腔内光子模和电子偏振与外部频率相关耗散浴的耦合。在真空Rabi频率与时间无关的情况下，得到了算符的精确解析表达式，它使我们能够表征腔对任意初始条件(真空、相干场、热激发)的量子耗散响应。对于光子模式和电子模式下的真空输入，腔系统的基态都是光子模式和电子模式下的有限布居的双模压缩真空态。然而，这些激发是虚的，不能从腔中逃逸：对于真空输入，找到了真空输出，没有任何腔内压缩的痕迹。对于相干光子输入，研究了线性光学响应谱(反射率、吸收、透射率)，并在极化本征模的不对称和特殊的反交叉中识别了超强耦合的特征。最后，我们计算了在非相干电子输入情况下的电致发光光谱：与孤立的无腔量子阱相比，超强耦合区的发射强度显著增强。
We present a full quantum theory for the dissipative dynamics of an optical cavity in the ultrastrong light-matter coupling regime, in which the vacuum Rabi frequency is a significant fraction of the active electronic transition frequency and the antiresonant terms of the light-matter coupling play an important role. In particular, our model can be applied to the case of intersubband transitions in doped semiconductor quantum wells embedded in a microcavity. The coupling of the intracavity photonic mode and of the electronic polarization to the external, frequency-dependent, dissipation baths is taken into account by means of quantum Langevin equations in the input-output formalism. In the case of a time-independent vacuum Rabi frequency, exact analytical expressions for the operators are obtained, which allows us to characterize the quantum dissipative response of the cavity to an arbitrary initial condition (vacuum, coherent field, thermal excitation). For a vacuum input in both the photonic and electronic polarization modes, the ground state of the cavity system is a two-mode squeezed vacuum state with a finite population in both photonic and electronic modes. These excitations are, however, virtual and cannot escape from the cavity: for a vacuum input, a vacuum output is found, without any trace of the intracavity squeezing. For a coherent photonic input the linear optical response spectra (reflectivity, absorption, transmission) have been studied, and signatures of the ultrastrong coupling have been identified in the asymmetric and peculiar anticrossing of the polaritonic eigenmodes. Finally, we have calculated the electroluminescence spectra in the case of an incoherent electronic input: the emission intensity in the ultrastrong coupling regime results in being significantly enhanced as compared to the case of an isolated quantum well without a surrounding cavity.