Backward and forward quasiphase matched multiwave SRS in nonlinear periodical structures

1
Backward and forward quasi-phase matched
multiwave SRS in nonlinear periodical structures
Victor G. Bespalov, Russian Research Center "S.
I. Vavilov State Optical Institute"
Nikolai S. Makarov, Saint-Petersburg State
Institute of Fine Mechanics and Optics (Technical
University)
2
Outline

• Principle of quasi-phase matching
• System of multiwave SRS equations
• Numerical simulations results
• Conclusions
• References

3
Principle of quasi-phase matching
Nonlinearity ?(3)
Nonlinearity ?(2)
Raman active medium
4
Principle of quasi-phase matching at SRS

• Generalized phase on active layers input do not
  practically change, that in a final result
  provides a realization of quasi-phase matching
  conditions

5
System of forward and backward multiwawe SRS
equations
?ji wave mismatching, gj steady-state Raman
gain coefficient, ?j frequencies of interacting
waves, Ej complex wave amplitudes
6
Model verification waves profiles at different
input pump intensities (left input pump and
right output pump)
I, GW/cm2
I, GW/cm2
t, ns
t, ns
7
Model verification waves profiles at different
input pump intensities (left output forward
Stokes and right output backward Stokes)
I, GW/cm2
I, GW/cm2
t, ns
t, ns
8
Raman gain dispersion
Barium nitrate
Hydrogen
9
Influence of high SRS components on calculations
precision

• For best calculation accuracy it is necessary to
  take into account at least the generation of 3
  Stokes and 3 anti-Stokes SRS components

10
The influence of backward SRS on QPM realization
(active layers length)
11
The influence of backward SRS on QPM realization
(passive layers length)
12
Conclusions

• Our model of forward and backward multiwave SRS
  is quality and quantity compared with
  experimental results
• For best accuracy of QPM SRS simulations it is
  necessary to take into account the dispersion of
  Raman gain coefficient
• For studying of multiwave SRS influence on QPM
  structure realization it is necessary to take
  into account the generation at least of 3 Stokes
  and 3 anti-Stokes SRS components
• The influence of backward SRS on QPM structure
  realization results in the small difference
  between layers length of optimal QPM structure
  and small decreasing of resulting anti-Stokes
  conversion efficiency (25 at backward and
  forward SRS, 30 at forward SRS)
• The oscillations of optimal layers length are
  partially connected with backward SRS influence
  and with insufficient precision of layers length
  determination due to high computational
  complexity of this task

13
References

• Armstrong J.A., Bloembergen N., Ducuing J.,
  Pershan P.S. // Phys. Rev., 1962, 127, pp.
  1918-1939.
• Bespalov V.G., Makarov N.S. Quasi-phase matching
  generation of blue coherent radiation at
  stimulated Raman scattering // Optics
  Communications 2002, 203 (3-6), pp. 413-420.
• Maier M., Kaiser W., Giordmaine J.A. Backward
  stimulated Raman scattering // Phys. Rev., 1969,
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• Raijun Chu, Morton Kanefsky, Joel Falk Numerical
  study of transient stimulated Brillouin
  scattering // J. Appl. Phys., 1992, V. 71, ?10,
  pp. 4653-4658.
• Zaporozhchenko R.G., Kilin S.Ya, Bespalov V.G.,
  Staselko D.I. Formation of the spectra of
  backward stimulated Raman scattering from the
  quantum noise of polarization of a scattering
  medium // Opt.Spectr., 1999, V. 86, ?4, pp.
  632-639.
• Bischel W.K., Dyer M.J. Wavelength dependence of
  the absolute Raman gain coefficient for the Q(1)
  transmission in H2 // J. Opt. Soc. Am. B, 1985,
  V. 3, pp. 677-682.