Figure 5
(a) Diffraction efficiency maps of the zone plates on chip 1 with a large difference in height between the back-side zone plate ZP1 and the front-side zone plate ZP2. (b) Diffraction efficiency maps of the zone plates on chip 2 with a small difference in height between the front- and back-side zone plates. The relative sizes (diameters) of the zone plates on the back-side and front-side are varied along the vertical axis in the grids and the diagonal offsets between them are varied along the horizontal axis. The red dashed line indicates the direction along which the offsets are made. |