Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10/136, 1040 Vienna, Austria.
Phys Rev Lett. 2013 Jul 12;111(2):023902. doi: 10.1103/PhysRevLett.111.023902.
The angular emission pattern of a random laser is typically very irregular and difficult to tune. Here we show by detailed numerical calculations that one can overcome the lack of control over this emission pattern by actively shaping the spatial pump distribution. We demonstrate, in particular, how to obtain customized pump profiles to achieve highly directional emission. Going beyond the regime of strongly scattering media where localized modes with a given directionality can simply be selected by the pump, we present an optimization-based approach which shapes extended lasing modes in the weakly scattering regime according to any predetermined emission pattern.
随机激光的角发射模式通常非常不规则，难以调节。在这里，我们通过详细的数值计算表明，可以通过主动控制空间泵浦分布来克服对这种发射模式的控制不足。我们特别演示了如何获得定制的泵浦轮廓来实现高度定向的发射。超越强散射介质的范围，在该范围中，可以通过泵浦简单地选择具有给定方向性的局域模式，我们提出了一种基于优化的方法，根据任何预定的发射模式来塑造弱散射范围内的扩展激光模式。
