| Phenomena such as resonant tunneling, radiative transition, and interactions between electrons, photons, and phonons are being investigated and utilized for THz QCL design and optimization. |
| Inside the phonon band DB are not possible since any resonance of the DB or harmonics with the extended phonons will radiate the DB away. |
| This issue is related to the inhibition of carrier relaxation due to the selection rule of interaction between electrons and phonons in discrete energy level systems. |
| Bose-Einstein distributions and photons, Debye theory of phonons. |
| These spontaneous fluctuations are driven by collective acoustic vibrational modes, known as phonons, in the gigahertz frequency range. |
| The broadness of the excited-state manifold is probably due to the strong electron coupling to high-frequency phonons, very recently suggested by Ihalainen et al. |
