The windows on hollow sphere surface. (a) The material deposition schematic on the edge of PS array; (b) the schematic of spherical crown. R, r, and θ are the sphere radius, circular radius on the top surface of spherical crown, and the angle related to r and R, respectively. (c) The total window size on hollow sphere surface varied as a function of the angle θ. Mode 1 represents the hollow sphere obtained through reshaping the nanoshell, modes 2 and 3 represent the hollow sphere with f
top = 30[0°, 0°]/f
= 30[θ, 0°] (mode 2) and f
top = 70[0°, 0°]/f
bottom = 30[80°, 30°] + 30[θ, 210°] (mode 3).