Intersubband Polaritons

Intersubband transitions are dipole allowed optical excitations between the quantized electronic levels within the conduction band of semiconductor heterostructures. The intersubband transition, when strongly coupled with one of the discrete modes of an optical resonator, does form new admixture states of photon and the material excitation, which are usually named as 'intersubband cavity-polaritons', following the excitionic terminology. They exhibit an anticrossing in energy with a separation known as 'vacuum-Rabi splitting', in analogy to the level-repulsion in the atomic physics phenomenon.