Oscillator strength for intraband transitions in (In,Ga)As/GaAs quantum dots

This letter reports on theoretical calculations of the oscillator strength associated with electron intraband transitions in (In,Ga)As/GaAs quantum dots. We study the effect of dot size and lateral separation between adjacent dots on the oscillator strength. The calculations indicate that transitions induced by p-polarized light from the electronic ground state to the first excited state are stronger than those induced by s-polarized light for large size dots with wide lateral interdot spacing. This situation changes, however, for small size dots in close proximity with one another. We discuss the relevance and implication of these results for applications in quantum-dot structures designed for mid-infrared detection.