Intraband absorption in InAs/GaAs self-assembled quantum dots

Using envelope function theory, intraband absorption is calculated for InAs/GaAs truncated pyramidal quantum dots. Strong in-plane polarized absorption from the first excited state occurs in the low mid-infrared region, while broadband z-polarized absorption features are located at higher frequencies. This polarization dependence is in agreement with experiment [Appl. Phys. Lett. 82,630(2003)] and is due to the dot geometry. The WL can induce both in-plane- and z-polarized absorption. For strong normal incidence photodetection, absorption from the first excited state should be exploited.