  Higher-order exceptional points have attracted increased attention in recent
years due to their enhanced sensitivity and distinct topological features.
Here, we show that nonlocal acoustic metagratings that enable precise and
simultaneous control over their muliple orders of diffraction, can serve as a
robust platform for investigating higher-order exceptional points in free
space. The proposed metagratings, not only could advance the fundamental
research of arbitrary order exceptional points, but could also empower
unconventional free-space wave manipulation for applications related to sensing
and extremely asymmetrical wave control.
