Quantum theory of light propagation III. Counter-propagating waves

M. D. Radchenko, Valeriy I. Yudin, M. Yu. Basalaev +4 more

G. B. Altshuller, Vyatcheslav B. Karasev, S. A. Kozlov +1 more

The nonlinear interaction of elliptically polarized counter-propagating waves in an isotropic transparent medium is analysed. Self-induced changes in the polarization of the counter-propagating light waves, are described. Using these results, a new type of modulator giving self-induced rotation of the polarization ellipse (SIRPE) is studied. The transmission of counter-propagating waves in the SIRPE modulator is shown to exhibit saturation with increase in light intensity and to be a multiple-valued function of the light intensity.

Milan Pospíchal

Zizhao Gan, Guozhen Yang

This paper is the third part of a series dealing with the theory of the coherent propagation of light in semiconductors. Based on the results of our previous papers, the "Maxwell-Bloch equations" describing the coherent propagation of light in semiconductors are derived. These equations are used to discuss a number of possible effects of the coherent propagation on both interband and exciton transitions. In particular, we analyze self-induced transparency and show that this effect can occur for both interband and exciton transitions.

Yaakov Shevy

The process of laser cooling in a quasi resonant standing laser wave is one of the principal techniques of laser cooling of free atoms. It will be shown that the nonlinear interaction between the counter propagating waves in a standing wave have a profound affect on the mechanical manifestations of the light on the atoms. This can be understood simply by noting that in the Two Wave Mixing (TWM) process, a momentum kick of 2ℏk is transferred to the atom, as a photon is absorbed from one wave and emitted into the counter propagating wave. This process is in fact responsible for the so called "Dipole force" Or "Stimulated Molasses" and has been verified experimentally!. However, since the TWM process requires high laser intensity under normal conditions it does not usually lead to lower equilibrium temperatures. Nevertheless, It has been shown that the TWM process can be modified when the normal decay rates of the atom are altered. This modification can give rise to the appearance of the TWM at lower intensity and can even change its lineshape. This in turn have an important implications on the laser cooling process in a standing wave. Among the important effects: (i) The appearance of the stimulated force at lower intensity when the dipole decay rate is increased by dephasing events.(ii) The appearance of a narrow resonance characterized by the ground state decay in an open system. (iii) The modification of the stimulated force when the quantum fluctuations of the vacuum field are modified by quadrature squeezing3. Processes (ii) and (iii) can change the sign of the stimulated force from a heating force to a cooling force at the red side of the atomic resonance and give additional cooling force much larger than the radiation pressure force.