Contribution to the theory of stimulated Raman emission in an optical resonator

V. N. Lugovoǐ

Georges G. Bret, François Gires, Guy Mayer

J.-G. Xie, Thomas E. Ruekgauer, Jilin Gu +3 more

We report the observation of coherent emission from a planar Fabry-Perot resonator driven by a single, coherently emitting microcavity. The microcavity, either a liquid microdroplet or microcylinder, emits coherent stimulated Raman scattering when irradiated by an intense pump laser; the Raman light, in turn, couples to modes of the resonator. The spatiotemporal characteristics of resonator emission are strongly influenced by the microcavity source within; notably, a significant excess time delay in the emission of stimulated Raman scattering (i.e., compared with that of the microcavity in free space) accompanies the appearance of a sharp resonator spatial interference pattern. This and other noteworthy features are described, and a qualitative discussion of their significance is given.

Y. R. Shen

Selected topics related to the fundamentals of nonlinear optics are discussed. First, a brief description on the theory of nonlinear optical susceptibilities is given. Emphasis is on the basic properties, on the recently developed bond theory, and on the dispersion of nonlinear susceptibilities. Then the coupled wave approach is discussed. It is shown that the transverse resonant excitation in material can be treated as a material excitational wave, and most nonlinear optics problems can be understood as results of coupling between em waves or em and material excitational waves. A number of examples of current interest are presented. These include sum- and difference-frequency generation, Raman scattering by coherent excitation, stimulated Raman and stimulated polariton scattering, four-wave mixing, and vibrational relaxation measurements. Finally, the physical distinction between laser emission and resonant stimulated Raman scattering in an optically pumped three-level system are considered. A similar problem on the distinction of hot luminescence and resonant Raman scattering has recently attracted much attention. It is shown that the hot laser action is connected directly with the population inversion, while the resonant stimulated Raman scattering is connected with transverse excitation. The problem is, however, more complicated for a multi-level system. (auth)

Махвиладзе Тариэль Михайлович, Leonid A. Shelepin

James J. Wynne, P. P. Sorokin

Stimulated emission in nineteen np-ns and np-(n-2)d transitions in K vapour was observed by optically pumping the np states with the second harmonic of a pulsed dye laser. The observed output wavelengths range from about 10 mu m to above 100 mu m. Wavelength measurements of the np-(n-2)d emissions can provide accurate unambiguous determinations of d-level energies. For the cases n=7 and n=8 stimulated Raman emission was observed at small detunings of the pump beam from the np resonance lines.