We report ultrathin photonic metagratings where anisotropic scattering is designed to achieve self-stabilizing dynamics in a collimated beam of laser light. Stability necessitates a delicate balance between all scattered orders of light, which we demonstrate in a monolithic material platform suited for efficient propulsion in space. Our suspended structures are fabricated in silicon nitride membranes, which is a promising lightsail material candidate due to its wafer-level scalability and favorable mechanical and optical properties. Lightsail prototype designs are optically characterized by angle-resolved photocurrent measurements of the intensities and angles of the asymmetric ±1 diffraction orders. We infer the optically induced forces and torques from refracted and reflected light measurements and show that these are restoring along one axis by providing them as input functions to numerical simulations of lightsail dynamics. Our experimental results represent a first step toward full dynamical verification of realistic lightsail designs and pave the way for realization of stable beam-riding lightsails composed of ultrathin dielectric membranes.

中文翻译：

---

用于自稳定的基于氮化硅元光栅的光帆的光学表征

我们报告了超薄光子元光栅，其中各向异性散射旨在实现准直激光束中的自稳定动力学。稳定性需要所有散射光之间的微妙平衡，我们在适用于太空高效推进的整体材料平台中证明了这一点。我们的悬浮结构是在氮化硅膜中制造的，由于其晶圆级可扩展性和良好的机械和光学性能，它是一种很有前途的光帆材料候选者。Lightsail 原型设计的光学特征是非对称 ±1 衍射级的强度和角度的角度分辨光电流测量。我们从折射和反射光测量中推断出光致力和扭矩，并通过将它们作为输入函数提供给光帆动力学的数值模拟，表明这些力和扭矩正在沿着一个轴恢复。我们的实验结果代表了对现实光帆设计进行全面动态验证的第一步，并为实现由超薄介电膜组成的稳定的光束骑行光帆铺平了道路。