Peculiarities of double photon intersubband transition in coherent transport triple-barrier structures

The closed form solution of Schrodinger equation is found, it describes resonant transitions which happen in the large-signal high-frequency electric fields for asymmetric triple-barrier resonant-tunneling structures with thin and high (delta) barriers. It is also shown that the most of electrons falling on the upper energy level can emit two photons and then leave the structure without intermediate electron-phonon interaction with 160% quantum efficiency limit.