All-optical switching by entangling quantum dot states in a photonic crystal cavity

We analyze the behaviour of a quantum dot embedded in a photonic crystal add-drop filter and in a direct coupled photonic crystal microcavity for optical signal processing applications. The joint effect of dipole induced transparency and electromagnetic induced transparency, considering a cascade configuration of the quantum dot, are used to modify the behaviour of the whole system. The mathematical model and a number of different conditions for tuning the frequency response of the filters are derived for application in all-optical switching and wavelength tunable devices.