Quasiphase matching antiStokes SRS generation

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Quasi-phase matching anti-Stokes SRS generation
Victor G. Bespalov All Russian Research Center
"S. I. Vavilov State Optical Institute"
Nikolai S. Makarov Saint-Petersburg State
Institute of Fine Mechanics and Optics (Technical
University)
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Outline

• Principals of quasi-phase matching
• Systems of SRS equations
• Numerical simulations results
• Conclusions
• References

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Principals of quasi-phase matching
?(2)
?(3)
Raman active medium
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System of transient SRS equations
? waves mismatching, g steady-state Raman
gain coefficient, ?i frequencies of interacting
waves, T2 dephasing time, q phonon wave, Aj
complex wave amplitudes.
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System of steady-state SRS equations
? waves mismatching, g steady-state Raman
gain coefficient, ?i frequencies of interacting
waves, Aj complex wave amplitudes.
In this system the waves mismatching and Raman
gain are the functions of coordinate for
nonlinear (?(3)?0) and linear (?(3)0) layers.
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Efficiency of anti-Stokes SRS generation in
Raman-active media
Hydrogen ? 3.84 rad/cm g 3.0 cm/GW.
- There is an optimal ratio Is/Ip, for maximal
conversion efficiency.
- The ratio depended from waves mismatching and
steady-state Raman gain coefficient.
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Energy conversion at quasi-phase matching
Hydrogen ? 3.84 rad/cm g 3.0 cm/GW Is(0)
0.0023 GW/cm2 efficiency ? 30
- At optimum ratio Is/Ip, conversion efficiency
reached more than 30, but Stokes intensity is
higher then anti-Stokes intensity.
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Comparison of quasi-phase and phase matching
Hydrogen ? 3.84 rad/cm g 3.0 cm/GW 1 -
quasi-phase matching 2 - without (quasi-) phase
matching 3 - phase matching
- Conversion efficiency at quasi-phase matching
is lower than at phase matching and higher than
at simple focusing in Raman media.
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Lengths of active and passive zones
- Similar plot can be achieved for barium nitrate.
- Structure of layers is not periodical.
- Lengths of active/passive layers are
monotonously decreased/ increased.
- It is essentially different from quasi-phase
matching in ?(2) media.
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Characteristic zone lengths
- It is possible to approximate this dependence
as La 2.6/? and Lp 3.9/?.
- With increasing of waves mismatching structure
become more periodical.
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Critical pump wave intensity
- There is a critical value of pump intensity.
- This dependence can be approximated as
Icr.p0.4?/g
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• Conclusions

- For each medium there is an optimal ratio
Is/Ip, at which conversion efficiency is
maximal. - The Conversion efficiency can reached
more than 30 - Structure of layers is not
periodical. Lengths of active layers are
monotonously decreased and lengths of passive
layers are monotonously increased. - With
increasing of waves mismatching structure become
more periodical. - For each medium there is a
critical value of pump intensity.
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• Acknowledgment

• I would like to thank
• SPIE - The International Society for Optical
  Engineering for registration fee.
• CRDF - US Civilian Research Development
  Foundation for support of my participation.

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• References

• R. B. Andreev, V. A. Gorbunov, S. S. Gulidov, S.
  B. Paperni, V. A. Serebryakov, About
  parametrical effects at SRS generation of higher
  components in gases, Quantum Electronics, 9(1),
  pp. 56-60, 1982.
• J. J. Ottusch, M. S. Mangir, D. A. Rockwell,
  Efficient anti-Stokes Raman conversion by
  four-wave mixing in gases J. Opt. Soc. Am., B 8,
  pp. 68-77, 1991.
• J. A. Armstrong, N. Blombergen, J. Ducuing, P. S.
  Pershan, Interaction between light waves in a
  nonlinear dielectric Phys. Rev., 127, pp.
  1918-1939, 1962.
• A. P. Hickman, W. K. Bischel, Theory of Stokes
  and anti-Stokes generation by Raman frequency
  conversion in the transient limit, Physical
  review A, 37(7), pp 2516-2523, 1988.
• Makarov N. S. (Scientist supervisor Bespalov V.
  G.) Generation of anti-Stokes SRS radiation in
  conditions of quasi-phase matching, in book
  Problems of coherent and nonlinear optics, pp.
  180-190.
• Bespalov V. G., Makarov N. S., Quasi-phase
  matching anti-Stokes SRS generation, Opt.
  Spectr., vol. , No. 5, 2001 (accepted for
  publication)

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