Bidirectional wavelength tuning of semiconductor quantum dots as artificial atoms in an optical resonator

We consider a pair of artificial atoms with different ground state energies. By means of finite element calculations we predict that the ground state energies can be tuned into resonance if the artificial atoms are placed into a flexible ring structure, which is elastically deformed by an external force. This concept is experimentally verified by embedding a low density of self-assembled quantum dots into the wall of a rolled up micro tube ring resonator. We demonstrate that quantum dots can elastically be tuned in- and out of resonance with each other or with the ring resonator modes.