Light confinement and mode splitting in rolled-up semiconductor microtube bottle resonators
Light confinement and mode splitting in rolled-up semiconductor microtube bottle resonators
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DOI：
10.1103/physrevb.85.155329
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发表时间：
2012-04
影响因子：
3.7
通讯作者：
C. Strelow;C. Schultz;H. Rehberg;M. Sauer;H. Welsch;A. Stemmann;C. Heyn;D. Heitmann;T. Kipp
中科院分区：
文献类型：
--
作者：
C. Strelow;C. Schultz;H. Rehberg;M. Sauer;H. Welsch;A. Stemmann;C. Heyn;D. Heitmann;T. Kipp
我们报告了由卷起的应变半导体双层形成的微管瓶谐振器中的受控光限制。我们从实验和理论上讨论了这种新型微腔的两个重要特性：轴向光限制和破缺旋转对称性的模式分裂。我们的模型基于圆模传播和轴向模传播的绝热分离。圆形问题通过针对沿微管轴的特定几何形状的简单波导模型来解决。这些解充当轴向传播的准薛定谔方程中的准势。我们通过实验研究了具有两种不同轴向限制机制的微管：滚动边缘中不同缠绕数量的叶瓣和沿微管轴不同壁厚的蚀刻环。对于具有波瓣的微管，我们观察到与我们的模型非常好的定量一致性，并表明轴向模式色散甚至可以通过波瓣的形状来定制。对于带有蚀刻环的微管，我们仅观察到定性的一致性。这些微管通过二维有限差分时域模拟分析，通过破坏旋转对称性表现出明显的模式分裂。我们观察到在绕数变化的情况下分裂幅度以及分裂模式的品质因数的振荡行为。我们证明分裂与轴向限制有关。
We report on the controlled light confinement in microtube bottle resonators formed by rolled-up strained semiconductor bilayers. We experimentally and theoretically discuss two important properties of this novel kind of microcavities: the axial light confinement and the mode splitting by broken rotational symmetry. Our model bases on the adiabatic separation of circular and axial mode propagation. The circular problem is solved by a simple waveguide model for the specific geometry along the microtube axis. These solutions act as a quasipotential in a quasi-Schrödinger equation for the axial propagation. We experimentally investigated microtubes with two different axial confinement mechanisms: lobes of varying winding number in the rolling edge and etched rings of a varying wall thickness along the microtube axis. For the microtubes with lobes, we observe a very good quantitative agreement with our model and show that axial mode dispersion can even be tailored by the shape of the lobe. For the microtubes with etched rings, we observe only a qualitative agreement. These microtubes exhibit a well pronounced mode splitting by broken rotational symmetry that is analyzed by two-dimensional finite-difference time-domain simulations. We observe an oscillating behavior of the amplitude of the splitting as well as of the quality factors of the split modes under variation of the winding number. We show that the splitting is connected to the axial confinement.