High Harmonic Generation in Ar and N2 Gas Mixture Using Ultrashort High Power Laser System

Abstract

High harmonic generation (HHG) has been accepted as a tool for tabletop based generation of light source in the XUV and soft x ray region. HHG can produce coherent optical pulses having pulse duration in the femtosecond or even attosecond time region. In this paper, generation of high harmonics are produced by using high power laser system having optical pulses at 6mj pulse energy with pulse duration of 50fs at 10Hz repetition rate. High harmonics in pure Ar, N2 and mixture of the Ar-N2 are used as a generation medium to produce high harmonics. The harmonic signal is increased or decreased depending on the experimental condition. Harmonic yield produced in Ar is stronger than harmonic yield produced in N2 gas. Generation of high order harmonics are observed up to 35H (~54eV corresponding photon energy), and harmonic order from N2 gas is 33H. The mixture of two gas species cause to enhancement of 35H order, which is weakly observed in pure N2 gas. The mechanism of high harmonic generation is explained that strong harmonic signal generated in pure Ar gas helps increase the ionization rate of N2 gas. Thus, the harmonic signal in Ar-N2 is boosted compared the harmonic signal produced in pure N2. The enhancement factor of harmonic yield is from ~2 to 5 for per harmonic order.

Keywords

• Ultrafast physics
• femtosecond laser
• high harmonic generation
• extreme ultraviolet
• attosecond science

References

1. Bartels R, Backus S, Zeek E, Misoguti L, Vdovin G, Christov IP, Murnane MM, Kapteyn HC, 2000. Shaped-Pulse Optimization of Coherent Emission of High-Harmonic Soft X-Rays. Nature, 406:164.
2. Corkum PB, 1993. Plasma Perspective on Strong-Field Multiphoton Ionization. Physical Review Letters, 71:1994-1997.
3. Drescher M, Hentschel M, Kienberger R, Uiberacker M, Yakovlev V, Scrinzi A, Westerwalbesloh T, Kleineberg U, Heinzmann U, Krausz F, 2002. Time-Resolved Atomic Inner-Shell Spectroscopy. Nature, 419(6909):803-807.
4. Falcão-Filho EL, Lai C-J, Hong K-H, Gkortsas V-M, Huang S-W, Chen L-J, Kärtner FX, 2010. Scaling of High-Order Harmonic Efficiencies with Visible Wavelength Drivers: A Route to Efficient Extreme Ultraviolet Sources. Applied Physics Letters, 97(6):061107.
5. Gibson E, Paul A, Wagner N, Tobey Ra, Backus S, Christov I, Murnane M, Kapteyn H, 2004. High-Order Harmonic Generation up to 250 Ev from Highly Ionized Argon. Physical Review Letters, 92(3):033001.
6. Krause JL, Schafer KJ, Kulander KC, 1992. High-Order Harmonic Generation from Atoms and Ions in the High Intensity Regime. Physical Review Letters, 68:3535-3538.
7. Lambert G, Hara T, Garzella D, Tanikawa T, Labat M, Carre B, Kitamura H, Shintake T, Bougeard M, Inoue S, Tanaka Y, Salieres P, Merdji H, Chubar O, Gobert O, Tahara K, Couprie ME, 2008. Injection of Harmonics Generated in Gas in a Free-Electron Laser Providing Intense and Coherent Extreme-Ultraviolet Light. Nature Physics, 4:296.
8. Li XF, L’Huillier A, Ferray M, Lompré LA, Mainfray G, 1989. Multiple-Harmonic Generation in Rare Gases at High Laser Intensity. Physical Review A, 39(11):5751-5761.

9. McPherson A, Gibson G, Jara H, Johann U, Luk TS, McIntyre IA, Boyer K, Rhodes CK, 1987. Studies of Multiphoton Production of Vacuum-Ultraviolet Radiation in the Rare Gases. Journal of the Optical Society of America B, 4(4):595-601.
10. Nabekawa Y, Hasegawa H, Takahashi EJ, Midorikawa K, 2005. Production of Doubly Charged Helium Ions by Two-Photon Absorption of an Intense Sub-10-Fs Soft X-Ray Pulse at 42 Ev Photon Energy. Physical Review Letters, 94(4):043001.
11. Paul PM, Toma ES, Breger P, Mullot G, Augé F, Balcou P, Muller HG, Agostini P, 2001. Observation of a Train of Attosecond Pulses from High Harmonic Generation. Science, 292(5522):1689-1692.
12. Salières P, Carré B, Le Déroff L, Grasbon F, Paulus GG, Walther H, Kopold R, Becker W, Milošević DB, Sanpera A, Lewenstein M, 2001. Feynman's Path-Integral Approach for Intense-Laser-Atom Interactions. Science, 292(5518):902-905.
13. Sandberg RL, Paul A, Raymondson DA, Hädrich S, Gaudiosi DM, Holtsnider J, Tobey RaI, Cohen O, Murnane MM, Kapteyn HC, Song C, Miao J, Liu Y, Salmassi F, 2007. Lensless Diffractive Imaging Using Tabletop Coherent High-Harmonic Soft-X-Ray Beams. Physical Review Letters, 99(9):098103.
14. Sayrac M, Kolomenskii AA, Anumula S, Boran Y, Hart NA, Kaya N, Strohaber J, Schuessler HA, 2015. Pressure Optimization of High Harmonic Generation in a Differentially Pumped Ar or H2 Gas Jet. Review of Scientific Instruments, 86(4):043108.
15. Sayrac M, Kolomenskii AA, Dong J, Schuessler HA, 2019. Generation of Enhanced Even Harmonics of Fundamental Radiation in Temporally Separated Two-Color Laser Fields. The Journal of Electron Spectroscopy and Related Phenomena, 233:22-27.
16. Sayrac M, Kolomenskii AA, Schuessler HA, 2018. Pressure Optimization and Phase Matching of High Harmonics Generation in Co2 and C2h2 Molecular Gases. The Journal of Electron Spectroscopy and Related Phenomena, 229:1-6.
17. Sayrac M, Kolomenskii AA, Schuessler HA, 2019. Pressure Dependence of High Order Harmonic Generation in Nitrogen Molecular Gas and Atmospheric Air. Optik, 179:994-1000.
18. Sayrac M, Kolomenskii AA, Strohaber J, Schuessler HA, 2015. High Harmonic Generation in Ne and H2 Gas Mixtures. Journal of the Optical Society of America B, 32(12):2400-2405.
19. Sekikawa T, Kosuge A, Kanai T, Watanabe S, 2004. Nonlinear Optics in the Extreme Ultraviolet. Nature, 432(7017):605-608.
20. Tate JT, Smith PT, 1932. The Efficiencies of Ionization and Ionization Potentials of Various Gases under Electron Impact. Physical Review, 39(2):270-277.
21. Vodungbo B, Gautier J, Lambert G, Sardinha AB, Lozano M, Sebban S, Ducousso M, Boutu W, Li K, Tudu B, Tortarolo M, Hawaldar R, Delaunay R, V. LF, Arabski J, Boeglin C, Merdji H, Zeitoun P, Lüning J, 2012. Laser-Induced Ultrafast Demagnetization in the Presence of a Nanoscale Magnetic Domain Network. Nature Communications, 3:999.
22. Womer R, 1931. Ionization of Helium, Neon, and Argon. Physical Review, 38(3):454-456.
23. Zhukovsky K, 2017. Generation of Coherent Soft X-Ray Radiation in Short Fel with Harmonic Multiplication Cascades and Two-Frequency Undulator. Journal of Applied Physics, 122(23):233103.
24. Zhukovsky K, 2017. High-Harmonic X-Ray Undulator Radiation for Nanoscale-Wavelength Free-Electron Lasers. Journal of Physics D: Applied Physics, 50(50):505601.
25. Zhukovsky K, 2017. Soft X-Ray Generation in Cascade Sase Fel with Two-Frequency Undulator. EPL (Europhysics Letters), 119(3):34002.
26. Zhukovsky KV, 2018. Generation of X-Ray Radiation in Free-Electron Lasers with Two-Frequency Undulators. Russian Physics Journal, 60(9):1630-1637.