Quantum Dots by QED
High quantum dot (QD) efficiency may be explained by excitons generated in the quantum electrodynamics (QED) confinement of electromagnetic (EM) radiation during the absorption of the laser radiation. There is general agreement that by the Mie theory laser photons are fully absorbed by QDs smaller than the laser wavelength. But how the absorbed laser photons are conserved by a QD is another matter. Classically, absorbed laser radiation is treated as heat that in a body having specific heat is conserved by an increase in temperature. However, the specific heats of QDs vanish at frequencies in the near infrared (NIR) and higher, and therefore an increase in temperature cannot conserve the absorbed laser photons. Instead by QED, the laser photon energy is first suppressed because the photon frequency is lower than the EM confinement frequency imposed by the QD geometry. To conserve the loss of suppressed EM energy, an equivalent gain must occur. But the only EM energy allowed in a QED confinement has a frequency equal to or greater than its EM resonance, and therefore the laser photons are then up-converted to the QD confinement frequency - the process called cavity QED induced EM radiation. High QD efficiency is the consequence of multiple excitons generated in proportion to very high QED induced Planck energy because at the nanoscale the EM confinement frequencies range from the vacuum ultraviolet (VUV) to soft x-rays (SXRs). Extensions of QED induced EM radiation are made to surface enhanced Raman spectroscopy (SERS) and light emission from porous silicon (PS).
S. J. CHUA, J. H. TENG, O. WADA, R. DE LA RUE and X. H. TANG
T. Prevenslik, "Quantum Dots by QED", Advanced Materials Research, Vol. 31, pp. 1-3, 2008