Spectral Properties of Stimulated Emission in a Broad Pumping Range

Mary Anne Moore, Vincent W. Barnett, W. R. Garrett

Michael L. Kliewer, A. Suchocki, Richard C. Powell

Solutions of the rate equations for a two-level system describing spectral properties in the presence of stimulated emission under picosecond-pulse pumping conditions are examined. The materials of interest are broad band tunable, vibronic laser crystals whose lasing properties under normal pumping conditions have been related to spectral properties through the McCumber theory1. The population inversion at threshold can then be determined by three methods: lifetime shortening, band narrowing, and peak gain measurements.

Vladimir I. Odintsov

H.-G. Unger

Guang S. He, Paras N. Prasad

Optical phase-conjugation properties of the backward-stimulated radiation from a two-photon-pumped frequency-upconversion lasing medium are studied. The gain medium is a new dye solution pumped with ∼11-ns and ∼1064-nm laser pulses; a highly directional and phase-conjugate backward-stimulated emission at ∼616-nm wavelength could be obtained with a net conversion efficiency of ∼10%. The spectral, temporal, and output–input characteristics of this kind of stimulated emission are presented in detail. The phase-conjugation properties of the backward-stimulated emission have been demonstrated by both the far-field (beam-divergence) measurement and the near-field (image-reconstruction) measurement. The wave-front reconstruction behavior is not perfect, especially under a larger aberration influence.

Guang S. He, Paras N. Prasad

Optical phase-conjugation properties of the backward stimulated radiation from a one-photon pumped lasing medium have been studied. The gain medium is a dye solution (pyrromethene 597 in ethanol) or the same dye doped poly(methyl methacrylate) (PMMA) rod pumped with /spl sim/7-ns and 532-nm laser pulses. A highly directional and phase-conjugate backward stimulated emission at /spl sim/573 nm wavelength could be obtained with a conversion efficiency of /spl sim/42% by using a 1-cm-long dye solution sample at the concentration level of d/sub 0/=0.000 15 mol/L. The spectral, temporal, output/input, and phase-conjugation properties of this backward stimulated emission are presented in detail. The induced aberration influence, which is much larger than the divergence angle of the input pump beam, can be basically removed by the backward stimulated emission; however, the fidelity of the near-field detail for the backward stimulated emission is relatively poor. A quasi-collinear holographic interaction model and a mathematical analysis are presented to explain the basic experimental results.