Figure 5
Variations in the lattice parameter map ([Delta]d/d map) of the [alpha]-SiO2 [\overline 4220] (X-cut) crystal. The map was taken on the dashed area a1 shown in Fig. 4[link](b). Dashed triangles in (a) are the areas where there is a surface flatness: (i) wedge area (due to the orientation flats provided by the manufacturer) and (ii) thickness variation area mostly due to the non-homogeneous etching procedure  [article HTML]