Vol. 26, issue 09, article # 2

Abstract:

The results of numerical simulation of the nonlinear propagation of high-power pulsed laser radiation at a wavelength of 10.6 microns in air upon Kerr self-focusing and filamentation are presented. The optical model of air involves cubic and higher optical nonlinearity, plasma nonlinear absorption and refraction, and air linear absorption. The single-filamentation regime of the laser pulse with peak power of up to few terawatts and pulse duration of one picosecond is studied. For the first time we show that in contrast to the filamentation in the near-infrared wavelength range, the specific feature of long wavelength radiation self-action in air is the formation of abnormally elongated and wide intense light channel followed by nearly continuous along the propagation direction plasma column. The peak electron density of the formed plasma column is comparable to that created by a femtosecond radiation in the near-infrared spectral range. The physical cause for these peculiarities is the change of air ionization regime by picosecond CO₂-laser pulses in favor of bound electrons tunneling through the atomic potential barrier and the progressive development of the electron avalanche.

Keywords:

ultrashort laser radiation, self-focusing, filamentation, ionization, laser plasma

References:

1. Zuev V.E., Zemljanov A.A., Kopytin Ju.D. Nelinejnaja optika atmosfery. L.: Gidrometeoizdat, 1989. 256p.
2. Gebhardt F.G. High power laser propagation // Appl. Opt. 1974. V. 15, N 6. P. 1479–1493.
3. Bravy B.G., Chernyshev Yu.A., Gordienko V.M., Makarov E.F., Panchenko V.Ya., Platonenko V.T., Vasil'ev G.K. Multi-terawatt picoseconds 10-μm СО₂ laser system: design and parameters' control //Opt. Express. 2012. V. 20, N 23. P. 25536–25544.
4. Polyanskiy M.N., Babzien M. Ultrashort pulses // CO₂ laser – optimization and application / Ed. D.C. Dumitras. InTech. ISBN 978-953-51-0351-6, 2012. P. 139–162.
5. Haberberger D., Tochitsky S., Joshi C. Fifteen terawatt picosecond CO₂ laser system // Opt. Express. 2010. V. 18, N 17. P. 17865–17875.
6. Polyanskiy M.N., Babzien M., Pogorelsky I., Yakimenko V. Ultrashort-pulse CO2 lasers: Ready for the race to petawatt? // XIX Int. Sympos. on High-Power Laser Systems and Applications: Proc. SPIE. 2012. V. 8677. 86770G.
7. Gordienko V.M., Platonenko V.T., Sterzhantov A.F. Samovozdejstvie moshhnogo desjatimikronnogo lazernogo izluchenija v gazovyh sredah: upravlenie dlitel'nost'ju impul'sa i generacija gorjachih jelektronov // Kvant. jelektron. 2009. V. 39, N 7. P. 663–668.
8. Rajzer Ju.P. Fizika gazovogo razrjada. M.: Nauka, 1987. 592 p.
9. Berge L., Skupin S., Nuter R., Kasparian J., Wolf J.-P. Ultrashort filaments of light in weakly ionized, optically transparent media // Rep. Prog. Phys. 2007. V. 70. P. 1633–1713.
10. Couairon A., Myzyrowicz A. Femtosecond filamentation in transparent media // Phys. Reports. 2007. V. 441, N 2–4. P. 47–189.
11. Kandidov V.P., Shlenov S.A., Silaeva E.P., Dergachev A.A. Filamentacija moshhnogo femtosekundnogo lazernogo izluchenija v vozduhe i ee prilozhenija v atmosfernoj optike // Optika atmosf. i okeana. 2010. V. 23, N 10. P. 873–884.
12. Gejnc Ju.Je., Zemljanov A.A., Kabanov A.M., Matvienko G.G. Nelinejnaja femtosekundnaja optika atmosfery / Pod obshhej red. prof. A.A. Zemljanova. Tomsk: Izdatelstvo Instituta optiki atmosfery SO RAN, 2010. 212 p.
13. Uchida S., Shimada Y., Yasuda H., Motokoshi S., Yamanaka C., Yamanaka T., Kawasaki Z., Tsubakimoto K. Laser-triggered lightning in field experiments // J. Opt. Technol. 1999. V. 66. P. 199–202.
14. Rodriguez M., Bourayou R., Méjean G., Kasparian J., Yu J., Salmon E., Scholz A., Stecklum B., Eislöffel J., Laux U., Hatzes A.P., Sauerbrey R., Wöste L., Wolf J.-P. Kilometer-range non-linear propagation of femtosecond laser pulses // Phys. Rev. E. 2004. V. 69. 036607.
15. Apollonov V.V., Pletnev N.V. Sozdanie protjazhennyh provodjashhih kanalov v atmosfere // Kvant. jelektron. 2012. V. 42, N 2. P. 130–139.
16. Kasparian J., Rodriguez M., Mejean G., Yu J., Salmon E., Wille H., Bourayou R., Frey S., Andre Y.-B., Mysyrowicz A., Sauerbrey R., Wolf J.-P., Wöste L. White-light filaments for atmospheric analysis // Science. 2003. V. 301, N 7. P. 61–64.
17. Shim B., Schrauth S.E., Gaeta A.L. Filamentation in air with ultrashort mid-infrared pulses // Opt. Express. 2011. V. 19, N 10. P. 9118–9126.
18. Brabec T., Krausz F. Nonlinear optical pulse propagation in the single-cycle regime // Phys. Rev. Lett. 1997. V. 78. P. 3282–3285.
19. Keldysh L.V. Ionizacija v pole sil'noj jelektromagnitnoj volny // Zh. jeksperim. i teor. fiz. 1964. V. 47. P.1945–1956.
20. Delone N.B., Krajnov V.P. Nelinejnaja ionizacija atomov lazernym izlucheniem. M.: Fizmatlit, 2001. 311 p.
21. Perelomov A.M., Popov V.S., Terent'ev M.V. Ionizacija atomov v peremennom jelektricheskom pole //Zh. jeksperim. i teor. fiz. 1966. V. 50. P. 1393–1397.
22. Loriot V., Hertz E., Faucher O., Lavorel B. Measurement of high-order Kerr refractive index of major air components: erratum // Opt. Express. 2010. V. 18, N 3. P. 3011–3012.
23. Ettoumi W., Petit Y., Kasparian J., Wolf J.-P. Generalized Miller Formulæ // Opt. Express. 2010. V. 18, N 7. P. 6613–6620.
24. Zhang J., Lu Z.H., Wang L.J. Precision refractive index measurements of air, N₂, O₂, Ar, and CO₂ with a frequency comb // Appl. Opt. 2008. V. 47, N 17. P. 3143–3151.
25. Daigle J.-F., Kosareva O., Panov N., Wang T.-J., Hosseini S., Yuanc S., Roy G., Chin S.L. Formation and evolution of intense, post-filamentation, ionization-free low divergence beams // Opt. Commun. 2011. V. 284, N 14. P. 3601–3606.
26. Ahmanov S.A., Vyslouh V.A., Chirkin A.S. Optika femtosekundnyh impul'sov. M.: Nauka, 1988. 312 p.