Ultrafast all-optical polarization QDs switch room temperature properties

All-optical switching consisting of Bragg-spaced quantum dots layers is investigated in theory. The quantum dots are applied in this switch for their spin-dependent polarization and ultrafast full recovery of the sample after passage of a circle-polarized control light. The circular dichroism and birefringence are induced, and the polarization of the signal pulse is changed, which can be applied to design the all-optical switch. This switching structure shows great advantages of lower requirement of pump light intensity, and is a promising candidate for the ultrafast all-optical switching devices at room temperature comparing to the similar quantum well structure.