Splitting of Vavilov-?erenkov radiation spectra in excited dispersing media

B. A. Veklenko

A. Yu. Sechin, A. N. Starostin, Yu. K. Zemtsov +2 more

Yu. K. Zemtsov, A. Yu. Sechin, А. Н. Старостин

F. Richter, Matthias Florian, K. Henneberger

We consider the interacting system of light and matter and present quantum-kinetically exact relations for the propagation of light through arbitrarily absorbing and dispersive steadily excited media in a specified geometry. We arrive at an energy flow law which may be regarded as a generalization of the Kirchhoff and Planck radiation laws to nonequilibrium. The field fluctuations are shown to generally split up into medium- and vacuum-induced contributions, of which only the latter governs the energy transport between the medium and the environment. A thorough derivation of the law is given and it is discussed together with interesting details in the underlying relations and physics. Especially, in the context of excited semiconductors, quasiequilibrium emission and lasing, as well as spectral features in the presence of quantum condensation are addressed.

V. E. Ogluzdin

Introduction-What happens to photons of laser radiation whose energy differs from the energy of the inter-level electronic transitions of atoms of the substance under study. According to Bohr and Einstein, the traditional scheme of interaction between radiation and matter includes the following processes: 1) resonant absorption of radiation, 2) spontaneous radiation, 3) resonant stimulated radiation. In the absence of resonance between the pumping frequency and the frequencies of electronic transitions in atoms alloying a dispersed medium, the interaction of radiation and matter is carried out due to the annihilation of pairs of pump radiation photons, the birth of axions and their subsequent decay into new photons whose energy differs from the energy of the pump photons. If in atomic vapors in the resonant case one photon is required for the transition of an electron from the ground level S to the excited P, then in the non-resonant case such a transition is possible due to the annihilation of a pair of photons.