Periodically-pumped organic microlasers

在本项目中，我们提出了具有有机活性介质的平面微腔中局域准模和超模形成的实验和理论研究。为此，应以空间非均匀的方式激发平面有机微腔，以诱导有机腔层内增益和吸收分布的空间调制。在有机微腔的周期性光泵浦实验中，将重点研究干涉模式。在这种情况下，我们的初步结果表明，相干性可以扩展到整个泵浦模式的平面内，不再受微腔模态体积的限制，微腔模态体积与平面结构相互作用，通常非常小。这一观察结果对未来有机微腔激光器的周期性电泵浦应用具有至关重要的意义。首先，由于相干性的面内传播，激光体积可能会扩大，这可能导致单模有机激光器的发射功率大大提高。其次，由于面内矢量的离散化导致相对于镜子法线的斜发射，因此相干光的传播矢量不再与电流流重合。这种光流与电激励的解耦减少了接触和电流的影响，这些影响是寄生的，会降低激光器的性能和特性。该项目的目的是获得平面微腔中空间相干过程的基本理解，并发展操纵这些过程的能力。与直接将不同结构合并到空腔层甚至该层的物理结构相比，使用周期性光泵浦在实验中提供了无与伦比的灵活性。它可以优化这些结构，以便将来加入金属触点，也可以更深入地了解微腔激光器的基本物理特性。

In this project, we propose the experimental and theoretical investigation of localised quasimodes and the formation of supermodes in planar microcavities having an organic active medium. To this end, the planar organic microcavities shall be excited in a spatially inhomogeneous fashion, to induce a spatial modulation of the distributions of gain and absorption within the organic cavity layer. A major effort will be put on the experiments which use an interference patterns for periodic optical pumping of organic microcavities. In this case, our preliminar results show that the coherence may extend in-plane over the entire pump pattern and is not restricted anymore by the mode volume of the microcavity, which is mutual to the planar structures and is typically very small. This observation is of crucial importance for the future applications which will involve a periodic electrical pumping of organic microcavity lasers. First of all it shows, that the lasing volume may be extended due to the in-plane propagation of the coherence, which might lead to much higher emission powers of a single-mode organic laser. Secondly, since discretization of the in-plane vector leads to an oblique emission with respect to the normal of mirrors, so that the propagation vector for the coherent light does not concide anymore with the electric current flow. This decoupling of the optical flow from the electrical excitation reduces the influence of the contacts and currents, which are parasitic and degrade laser performance and characteristics.The aim of the project is to obtain a basic understanding of spatially coherent processes in a planar microcavity, and to develop the ability to manipulate these processes. In contrast to the direct incorporation of different structures into the cavity layer or even physical structuring of this layer, the use of the periodic optical pumping offers an incomparable flexibility in the experiments. It allows both to optimize these structures for the future incorporation of e.g. metal contacts and also to obtain a deeper understanding of the fundamental physics of microcavity lasers.