Resonance interaction between electrons and photons

K S Baliyan

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.

Angela Thränhardt

This chapter considers electron–photon interaction, i.e., light–matter coupling. It introduces the theoretical treatment of electron–photon interaction for different and mostly strongly simplified cases. In resonator structures, calculation of the appropriate photon modes is required to allow access to the strength of electron–photon coupling. The general guideline is that light may be treated as a wave when propagating in vacuum, yet it has to be quantized in the case of the interaction with matter. In any ensemble of atoms or molecules in interaction with an electromagnetic field, there are three processes occurring: spontaneous emission, absorption, and stimulated emission. In order to get a flavor of a many-body treatment of electron–photon interaction, the derivation of the semiconductor Bloch equations will be discussed briefly. The strength of the light field at the location of the electron determines the interaction strength between light and matter.

Itikawa, Y

V. I. Anikin, S V Kryuchkov, V. E. Ogluzdin

An experimental investigation was made of the resonant stimulated electronic Raman scattering near the principal doublet of potassium. A study was made of the dispersion, interaction of two- and three-photon scattering, and influence of four-photon processes. Possible mechanisms of the population of the 4 2 P 1/2 and 4 2 P 3/2 potassium levels were considered. The possibility of phase-matched four-photon parametric interactions in the investigated part of the spectrum was confirmed theoretically.

Helmut Schwarz