Fig. 1

Absorption images of a DRIE and an X-LIGA grating obtained with a monochromatic beam of 45 keV at the TOMCAT beamline. The DRIE grating exhibits an essentially period pattern indicating uniform and dense Au filling. The dark features arise from the bridges in the silicon template. The X-LIGA grating shows irregularities depicting areas with lower absorption that propagate through the grating. The colorbar values indicate the negative logarithm of the ratio in intensity with and without the grating in the beam (i.e., absorption in gold yielding higher values). Higher average absorption in the DRIE gratings, despite shallower grating height, arises from a decrease in the effective duty cycle due to the trapezoidal trench shape.