(color online) Control of the tilting angle ( of SMP pillars coated with a thin layer of metal. (a) Schematics of metal coating. Top-view (b) and side-view (c) SEM images of SMP pillars tilted at different θ depending on the thickness of Au coating, which is increased by ∼6.44 nm/increment from left (0 nm) to right (25.8 nm) (from Ref. [54], Fig. 1).