J. Phys. II France
Volume 2, Numéro 4, April 1992
Page(s) 727 - 747
DOI: 10.1051/jp2:1992162
J. Phys. II France 2 (1992) 727-747

From linear amplification to triggered superradiance : illustrative examples of stimulated emission and polarization spectroscopy for sensitive detection of a pulsed excited forbidden transition

M.A. Bouchiat, J. Guéna, Ph. Jacquier, M. Lintz and L. Pottier

Laboratoire de Spectroscopie Hertzienne, Département de Physique de l'ENS, 24 rue Lhomond, 75231 Paris Cedex 05, France

(Received 27 December 1991, accepted 17 January 1991)

This paper presents our experimental strategy for detecting an electric-field controlled pulsed-excited highly forbidden transition such as the 6S-7S transition of the Cs atom. The amplification of a pulsed probe beam close to resonance for one hfs component of the 7S - 6P 3/2 transition is monitored. Furthermore the polarization modification experienced by the probe beam as a result of its interaction with the vapor is meticulously analysed. In convincing examples we point out the high sensitivity and complete selectivity of the method for the angular anisotropy of the 7S state, such as orientation or alignment created in the 6S-7S excitation process. We illustrate the flexibility of the method by varying the pump-probe delay, or by changing the relative positions of the beams or the magnitude of the E-field that directly controls the optical gain. A smooth transition from linear amplification to triggered superradiance is observed which necessitates readjustment of the probe intensity for optimal detection. We demonstrate the vapor-induced enhancement of the amplification anisotropy, expected at high optical density.

32.70 - 32.80B - 42.65G - 35.10W

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