Kinetics And Optical Properties Of The Strongly Driven Gas Medium Of Interacting Atoms

ORAL

Abstract

This paper investigates stimulated emission and absorption near resonance for a driven system of interacting two-level atoms. Microscopic kinetic equations for the density matrix elements of N-atom states including atomic motion are built, taking into account atom-field and atom-atom interactions. Analytical solutions are given for the resulting macroscopic equations in different limits, for the system composed of a strong coherent ``pump'' field and a weak counter-propagating ``probe'' field. It was shown that the existence of a dipole-dipole (long-range) interaction between atoms separated by distance less than the pump wave-length can cause the formation of periodic polarization and population structures (gratings in time and space) in the pumped medium without a probe field. The ``interaction'' between pump and probe induced polarization/population gratings through a dipole-dipole interaction mechanism causes the absorption line shape asymmetry. This asymmetry is revealed in increasing probe gain for the ``red''-shifted (relative to pump) probe and suppressing the gain for the ``blue''-shifted probe field when pump is ``red''- shifted relative to the ensemble averaged resonant frequency. The theoretical results are consistent with experimental data for the probe gain as the function of frequency and atomic density for sodium vapor with the pump laser tuned near $D_{2}$ line. Here the dependance of gain on particle density was explained in the terms of the long-range interaction between the atoms.

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Authors

  • Andrii Sizhuk

    Physics Department, TAMU 77843

  • Allan Headley

    Texas A\&M, Sam Houston State University, Southern Methodist University, Dept of Physics, Texas Tech University, Depts of Cell Physiology and Molecular Biophysics, Texas Tech University HSC, Texas Tech University, Lee College, Texas A\&M University, Texas A\&M Univ.-Commerce, University of North Texas, Texas A\&M University and Princeton University, Princeton University, The University of North Texas, University of Texas at Austin, Center for High Energy Density Science, University of Texas at Austin, Institute for Fusion Studies, University of Texas at Austin, UT Arlington, Stephen F. Austin State University, Texas A&M University--Commerce, University of Texas at Dallas, University of Texas at El Paso, Department of Physics, The University of Texas at Dallas, Department of Physics and Astronomy, Francis Marion University, University of Texas at Brownsville, Texas State University--San Marcos, UTSA, Northwestern University, Rice University, Abilene Christian University, Texas Southern University, Department of Physics, Southern Methodist University, Dallas, Texas A\&M University Cyclotron Institute, Sciprint.org, University of Texas MD Anderson Cancer Center, University of Texas at San Antonio, Paschal High School, Fort Worth, TX, Department d'Enginyeria Electronica, Universitat Autonoma de Barcelona, Department of Physics, Texas State University at San Marcos, Texas State University at San Marcos, Angelo State University, Texas State University-San Marcos, Department of Surgery, The University of Texas Southwestern Medical Center, Dallas, TX 75390, Department of Medicine, Baylor College of Medicine, Department of Bioengineering, Rice University, Department of Physics and Astronomy, Rice University, Department of Surgery, University of Texas Southwestern Medical Center, University of Texas at Dallas, Physics, Viginia State University, Jefferson Laboratory, Trinity University, LIGO, UTB-TSC, Mount Holyoke College, Texas A&M University, Electrical and Computer Engineering, TAMU, American Institute of Physics, University of Texas at Arlington, Texas Christian University, Fort Worth, TX, University of Pennsylvania, Philadelphia, PA, University of Missouri-Columbia, Columbia, MO, Paine College, Augusta, GA, Univ. of Edinburgh, INFN-LNS, INFN LNS CATANIA ITALY, Arkansas Technical University, AR, USA, Cyclotron Institute Texas A\&M University College Station Usa, and Heather Galloway, Texas State University--San Marcos