Intersubband polariton

Intersubband transitions are dipole and are allowed optical excitations between the quantized electronic energy levels within the conduction band of semiconductor heterostructures. Intersubband transitions when coupled with an optical resonator form new, mixed-state photons. This mixing is referred to as an 'intersubband cavity-polariton'. These transitions exhibit an anticrossing in energy with a separation known as 'vacuum-Rabi splitting', similar to level repulsion in atomic physics.