Spectrum evolutions of spontaneous and pump-depleted stimulated Brillouin scatterings in liquid media
Gao Wei(高玮)a)b), Lü Zhi-Wei(吕志伟)a)†, He Wei-Ming(何伟明)a), Hasi Wu-Li-Ji(哈斯乌力吉)a), and Zhang Zan(张赞)a)
a Institute of Opto-Electronics, Harbin Institute of Technology, Harbin 150001, China; b Department of Applied Physics, Harbin University of Science and Technology, Harbin 150080, China
Abstract A theoretical model for calculating spontaneous and stimulated Brillouin scattering(SBS) spectra is described. An empirical formula for the Stokes output spectral linewidth, a function of spontaneous Brillouin linewidth and the exponential gain coefficient, is obtained by the calculated data fitting. The formula holds true for two cases involving pump undepletion and depletion. The lineshape change from spontaneous to highly pump-depleted SBS spectra is also investigated. The result shows that for the pump power below the SBS threshold, the Stokes output spectral lineshape evolves from Lorentzian to approximately Gaussian as the pump power increases. For the pump power near or beyond the threshold, the SBS spectrum is in the form of a steady Gaussian profile, and the spectral linewidth comes to a certain value about 7 times narrower than the spontaneous one. The theoretical results are experimentally demonstrated by using several common liquid media.
Received: 22 March 2008
Revised: 20 April 2008
Accepted manuscript online:
PACS:
78.35.+c
(Brillouin and Rayleigh scattering; other light scattering)
(Doped-insulator lasers and other solid state lasers)
Fund: Project supported by
the National Natural Science Foundation of China (Grant No
60778019), the Program of Excellent Team in Harbin Institute of
Technology, China, and the Program of Science and Technology of
Education the Bureau of Heilongjiang Province, China (Grant No
11521048).
Cite this article:
Gao Wei(高玮), Lü Zhi-Wei(吕志伟), He Wei-Ming(何伟明), Hasi Wu-Li-Ji(哈斯乌力吉), and Zhang Zan(张赞) Spectrum evolutions of spontaneous and pump-depleted stimulated Brillouin scatterings in liquid media 2008 Chin. Phys. B 17 3765
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