Victor G. Bespalov, Russian Research Center "S. I. Vavilov State Optical Institute"

1. The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering 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 The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru • Principle of quasi-phase matching • System of multiwave SRS equations • Numerical simulations results • Conclusions • References

3. Principle of quasi-phase matching Lк I2w Lк (3)0 (3)=0 H2 H2 H2 H2 c-axis z The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru d31 Nonlinearity(3) Nonlinearity(2) Raman active medium

4. Principle of quasi-phase matching at SRS , rad (3)0 (3)=0 The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru • 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 The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru 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) The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru 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) The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru I, GW/cm2 I, GW/cm2 t, ns t, ns

8. Raman gain dispersion The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru Barium nitrate Hydrogen

9. Influence of high SRS components on calculations precision The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru • 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) The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru

11. The influence of backward SRS on QPM realization (passive layers length) The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru

12. The influence of Stokes input intensity on anti-Stokes generation efficiency The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru

13. The influence of Stokes input pulse duration on anti-Stokes generation efficiency The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru

14. The influence of pump input intensity on anti-Stokes generation efficiency The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru

15. The influence of pump input pulse duration on anti-Stokes generation efficiency The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru

16. The influence of pump wavelength on anti-Stokes generation efficiency The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru

17. Conclusions The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru • 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 effective anti-Stokes SRS generation occurs in a wide range of input radiation parameters

18. References The efficient generation of anti-Stokes radiation at multiwave forward and backward stimulated Raman scattering; Saint-Petersburg, 12-17 October 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru • 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, V. 177, №2, pp. 580-599. • 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., Stasel’ko 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.