1] Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria [2] Center for Micro- and Nanostructures, Vienna University of Technology, A-1040 Vienna, Austria [3].
1] Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna, Austria [2].
Nat Commun. 2014 Jun 13;5:4034. doi: 10.1038/ncomms5034.
When two resonant modes in a system with gain or loss coalesce in both their resonance position and their width, a so-called exceptional point occurs, which acts as a source of non-trivial physics in a diverse range of systems. Lasers provide a natural setting to study such non-Hermitian degeneracies, as they feature resonant modes and a gain material as their basic constituents. Here we show that exceptional points can be conveniently induced in a photonic molecule laser by a suitable variation of the applied pump. Using a pair of coupled microdisk quantum cascade lasers, we demonstrate that in the vicinity of these exceptional points the coupled laser shows a characteristic reversal of its pump dependence, including a strongly decreasing intensity of the emitted laser light for increasing pump power.
当一个具有增益或损耗的系统中的两个共振模式在它们的共振位置和带宽上同时合并时，就会出现所谓的异常点，它在各种系统中充当非平凡物理的源。激光为研究这种非厄米简并提供了一个自然的环境，因为它们具有共振模式和增益材料作为其基本组成部分。在这里，我们通过适当改变泵浦的应用，在光子分子激光中方便地诱导出异常点。我们使用一对耦合的微盘量子级联激光器，证明了在这些异常点附近，耦合激光器表现出其泵浦依赖性的特征反转，包括随着泵浦功率的增加，发射激光的强度强烈减小。
