Colloidal photonic hetero-crystals with controllable coupling

Functionality of photonic hetero-crystals is defined by the mechanism and details of the light coupling at the hetero-interface. The methods to change this coupling include (i) the mismatch of the photonic band structures of the hetero-crystal counterparts, (ii) embedding the resonator at the interface or (iii) adding the coupling/decoupling elements. One of peculiar properties of the photonic hetero-crystals is the support of the propagating evanescent surface waves at the interface. These surface states relate to the Tamm states at the surface of atomic crystals. In accord to theoretical modelling, the realisation of surface waves in photonic heterocrystals requires overlap of the photonic bandgaps on the both sides of the interface.