Mossman M E, Bersano T M, Forbes Michael McNeil, Engels P
Department of Physics and Astronomy, Washington State University, Pullman, WA, 99164, USA.
Department of Physics and Biophysics, University of San Diego, San Diego, CA, 92110, USA.
Nat Commun. 2021 Dec 10;12(1):7226. doi: 10.1038/s41467-021-27555-3.
Typically discussed in the context of optics, caustics are envelopes of classical trajectories (rays) where the density of states diverges, resulting in pronounced observable features such as bright points, curves, and extended networks of patterns. Here, we generate caustics in the matter waves of an atom laser, providing a striking experimental example of catastrophe theory applied to atom optics in an accelerated (gravitational) reference frame. We showcase caustics formed by individual attractive and repulsive potentials, and present an example of a network generated by multiple potentials. Exploiting internal atomic states, we demonstrate fluid-flow tracing as another tool of this flexible experimental platform. The effective gravity experienced by the atoms can be tuned with magnetic gradients, forming caustics analogous to those produced by gravitational lensing. From a more applied point of view, atom optics affords perspectives for metrology, atom interferometry, and nanofabrication. Caustics in this context may lead to quantum innovations as they are an inherently robust way of manipulating matter waves.
焦散通常在光学背景下进行讨论，它是经典轨迹（光线）的包络线，在这里态密度发散，从而产生明显的可观测特征，如亮点、曲线和扩展的图案网络。在此，我们在原子激光的物质波中产生焦散，为在加速（引力）参考系中应用于原子光学的突变理论提供了一个引人注目的实验示例。我们展示了由单个吸引势和排斥势形成的焦散，并给出了一个由多个势产生的网络示例。利用原子内部状态，我们展示了流体流动追踪作为这个灵活实验平台的另一种工具。原子所经历的有效引力可以通过磁梯度进行调节，形成类似于引力透镜产生的焦散。从更实际应用的角度来看，原子光学为计量学、原子干涉测量和纳米制造提供了前景。在这种情况下，焦散可能会带来量子创新，因为它们是一种本质上稳健的操纵物质波的方式。
