Preu S, Schmid S I, Sedlmeir F, Evers J, Schwefel H G L
University of Erlangen-N¨urnberg, D-91058 Erlangen, Germany.
Opt Express. 2013 Jul 15;21(14):16370-80. doi: 10.1364/OE.21.016370.
In the Terahertz (THz) domain, we investigate both numerically and experimentally the directional emission of whispering gallery mode resonators that are perturbed by a small scatterer in the vicinity of the resonators rim. We determine quality factor degradation, the modal structure and the emission direction for various geometries. We find that scatterers do allow for directional emission without destroying the resonator's quality factor. This finding allows for new geometries and outcoupling scenarios for active whispering gallery mode structures such as quantum cascade lasers and passive resonators such as evanescent sensors. The experimental results agree well with finite difference time domain simulations.
在太赫兹（THz）频段，我们通过数值模拟和实验研究了回音壁模式谐振器的定向发射，该谐振器在靠近其边缘处受到一个小散射体的扰动。我们确定了各种几何形状下的品质因数退化、模态结构和发射方向。我们发现，散射体确实能够实现定向发射，而不会破坏谐振器的品质因数。这一发现为诸如量子级联激光器等有源回音壁模式结构以及诸如倏逝波传感器等无源谐振器带来了新的几何形状和外耦合方案。实验结果与时域有限差分模拟结果吻合良好。
