Abstract:
A paradoxical decrease in the generation threshold of high Stokes and anti-Stokes components of stimulated Brillouin scattering in water has been detected for the first time to our knowledge upon the displacement of the caustic of a focused laser beam from the bulk of water to air. The mechanism of generation of components caused by the four-wave mixing on counterpropagating beams when the water surface serves as the mirror of an induced cavity of a stimulated Brillouin laser is discussed. An upper bound R≪0.02 has been obtained for the reflection coefficient R of distributed feedback at stimulated Brillouin scattering in water.
This work was supported by the Russian Science Foundation (project no. 19-19-00712, fabrication of a biharmonic laser for the lidar monitoring of the deformation of the Earth’s crust in terms of the variation of magmatic gases) and by the Ministry of Science and Higher Education of the Russian Federation (subsidy identifier 075-15-2020-774 for large scientific projects in priority areas of scientific and technological development, biharmonic pumping of gigahertz resonances to study the remote action on the tobacco mosaic virus).
Citation:
S. M. Pershin, A. F. Bunkin, M. A. Davydov, A. N. Fedorov, M. Ya. Grishin, “New stimulated brillouin laser with an induced cavity”, Pis'ma v Zh. Èksper. Teoret. Fiz., 112:7 (2020), 437–442; JETP Letters, 112:7 (2020), 399–404