Accession Number : ADA300806

Title :   Two-Photon Cooperative Cascade Superfluorescence.

Descriptive Note : Final rept. May 92-Aug 95,

Corporate Author : COLUMBIA UNIV NEW YORK DEPT OF PHYSICS

Personal Author(s) : Hartmann, S. R.

PDF Url : ADA300806

Report Date : 13 OCT 1995

Pagination or Media Count : 7

Abstract : We present a study of the time development of an ensemble or three-level atoms which have been put in a coherent superposition of their ground and excited states (of the same parity) by the application of a short two-photon resonant laser pulse. We worked with Cs vapor where these states are labeled 6 S sub 1/2 and 6 D sub 3/2. Following the laser excitation, the intermediate 6 P sub 1/2 was empty and the high gain on the 6 sub 3/2 - 6 P sub 1/2 transition allowed superfluorescence (SF) to develop. We observed SF both along and against the direction of the laser excitation pulse. Our working parameters ensured that the SF developed long after the application of the excitation so that parametric amplification processes were not present. We found that, contrary to intuition, SF developed first against the laser direction. We also found that SF was more intense in this backward direction. We also found that SF cascades all the way to the ground state and that quantum beats associated with the hyperfine splitting of the 6 P sub 1/2 state were present. In the forward direction radiation appeared simultaneously on both upper and lower transitions. In the presence of a transverse magnetic field we observed time-delayed second harmonic generation.

Descriptors :   *FLUORESCENCE, *PHOTONS, RADIATION, MAGNETIC FIELDS, PARAMETERS, SECOND HARMONIC GENERATION, EXCITATION, QUANTUM THEORY, COHERENCE, ORIENTATION(DIRECTION), ATOMS, PULSED LASERS, LASERS, TIME, RESONANCE, DELAY, TRANSITIONS, GROUND STATE, SPLITTING, PARITY, BEAT SIGNALS, TRANSVERSE, HYPERFINE STRUCTURE, HIGH GAIN, PARAMETRIC AMPLIFIERS.

Subject Categories : Physical Chemistry
      Lasers and Masers
      Optics
      Nuclear Physics & Elementary Particle Physics
      Quantum Theory and Relativity

Distribution Statement : APPROVED FOR PUBLIC RELEASE