Figure 3.

Cross sections of four different QDs.(a) Circularly shaped cross section, considered to have a perfect symmetry, i.e., zero FSS. (b) Elliptically shaped cross section. (c) Same as presented in (b), but with a tilted orientation direction. (d) Cross section of arbitrary shape. The black arrows in (b), (c) and (d) indicate the direction of a unidirectional tuning technique.