Backward and forward quasi-phase 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 Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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 Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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 Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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 Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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) Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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) Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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 Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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 Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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) Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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) Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 2003 Makarov N.S., mak_nick@newmail.ru Bespalov V.G., bespalov@admiral.ru

12. Conclusions Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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 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 Backward and forward quasi-phase matched multiwave SRS in nonlinear periodical structures; Saint-Petersburg, 30 June – 2July 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.