Muhammed SAYRAÇ

Yüksek Güçlü Lazer Sistemi Kullanılarak N2 ve H2 Gaz Karışımında Koherent XUV Radyasyonunun Üretilmesi

Saf H2, saf N2 ve bunların 1:1 oranında karışımları yüksek harmonik üretiminde çalışılmıştır. 17H'den 35H'ye kadar olan harmonik mertebeler gözlemlendi. Saf H2'den üretilen harmonik spektrum elde edildi, ancak harmonik sinyal, saf N2 ve bunların karışımından üretilen harmonik spektruma kıyasla daha zayıftır. Gaz karışımındaki harmonik verim, saf H2'den gelen harmoniklere kıyasla artar. Harmonik mertebelerin ulaşabileceği maksimum foton enerjisi, iyi bilinen cutoff formülü ile hesaplandı. Deney ve hesaplama sonuçlarıyla elde edilen harmonik mertebeler bir uyum içindedir. N2:H2 karışımında, plato bölgesi harmoniklerine kıyasla daha yüksek harmonikler geliştirilmiştir. Saf N2 veya H2-N2 karışımında 35H mertebelerinde saf H2'ye göre artış gözlendi.

Anahtar Kelimeler:

atomik ve moleküler fiziği, gaz karışımı, femtosaniye lazer, yüksek harmonik üretimi, aşırı ultraviyole(XUV)

Generation of Coherent XUV Radiation in Gas Mixture of N2 and H2 using High Power Laser System

High harmonic generation is studied in gas species, namely pure H2, pure N2 and their mixture in 1:1 ratio. Observation of harmonic orders from 17H to 35H orders are well resolved. Harmonic spectrum produced from pure H2 are obtained, but the harmonic signal is weaker compared to that produced from pure N2 and from their mixture. Harmonic yield in gas mixture is enhanced compared to that from pure H2. The maximum photon energy that harmonic orders can reach is calculated with the well know cutoff formula. The experiment and the calculation results are in close agreement. In mixture of N2:H2, the higher harmonics are enhanced compared the plateau region harmonics. The enhancement of 35H orders in pure N2 or H2-N2 mixture is observed compared to pure H2.

Keywords:

Atomic and molecular physics, gas mixture, femtosecond laser, high harmonic generation, extreme ultraviolet (XUV),

PDF

___

Bleakney, W. (1932). “The ionization potential of molecular hydrogen”, Physical Review Letters, 40, 496-501.
Brizuela, F., Heyl, C. M., Rudawski, P., Kroon, D., Rading, L., Dahlström, J. M., Mauritsson, J., Johnsson, P., Arnold, C. L., and L'Huillier, A. (2013). “Efficient high-order harmonic generation boosted by below-threshold harmonics”, Scientific Reports, 3, 1410.
Chang, Z., and Corkum, P. (2010). “Attosecond photon sources: the first decade and beyond”, Journal of the Optical Society of America B, 27, B9-B17.
Corkum, P. B. (1993). “Plasma perspective on strong field multiphoton ionization”, Physical Review Letters, 71, 1994-1997.
Eisebitt, S., Luning, J., Schlotter, W. F., Lorgen, M., Hellwig, O., Eberhardt, W., and Stohr, J. (2004). “Lensless imaging of magnetic nanostructures by X-ray spectro-holography”, Nature, 432, 885-888.
Haessler, S., Caillat, J., and Salières, P. (2011). “Self-probing of molecules with high harmonic generation”, The Journal of Physics B: Atomic, Molecular and Optical Physics, 44, 203001.
Hentschel, M., Kienberger, R., Spielmann, C., Reider, G. A., Milosevic, N., Brabec, T., Corkum, P., Heinzmann, U., Drescher, M., and Krausz, F. (2001). “Attosecond metrology”, Nature, 414, 509-513.
Ishikawa, K. (2003). “Photoemission and ionization of He+ under simultaneous irradiation of fundamental laser and high-order harmonic pulses”, Physical Review Letters, 91, 043002.
Itatani, J., Levesque, J., Zeidler, D., Niikura, H., Pepin, H., Kieffer, J. C., Corkum, P. B., and Villeneuve, D. M. (2004). “Tomographic imaging of molecular orbitals”, Nature, 432, 867-871.
Kanai, T., Takahashi, E. J., Nabekawa, Y., and Midorikawa, K. (2007). “Destructive interference during high harmonic generation in mixed gases”, Physical Review Letters, 98, 153904.
Kapteyn, H. C., Murnane, M. M., and Christov, I. P. (2005). “Extreme nonlinear optics: Coherent X rays from lasers”, Physics Today, 58, 39-44.
Lewenstein, M. (2002). “Resolving physical processes on the attosecond time scale”, Science, 297, 1131-1132.
Lewenstein, M., Balcou, P., Ivanov, M. Y., L’Huillier, A., and Corkum, P. B. (1994). “Theory of high-harmonic generation by low-frequency laser fields”, Physical Review A, 49, 2117-2132.
Paul, P. M., Toma, E. S., Breger, P., Mullot, G., Augé, F., Balcou, P., Muller, H. G., and Agostini, P., (2001). “Observation of a train of attosecond pulses from high harmonic generation”, Science, 292, 1689-1692.
Popmintchev, T., Chen, M. C., Arpin, P., Murnane, M. M., and Kapteyn, H. C. (2010). “The attosecond nonlinear optics of bright coherent X-ray generation”, Nature Photonics, 4, 822-832.
Ravasio, A., Gauthier, D., Maia, F. R. N. C., Billon, M., Caumes, J. P., Garzella, D., Géléoc, M., Gobert, O., Hergott, J. F., Pena, A. M., Perez, H., Carré, B., Bourhis, E., Gierak, J., Madouri, A., Mailly, D., Schiedt, B., Fajardo, M., Gautier, J., Zeitoun, P., Bucksbaum, P. H., Hajdu, J., and Merdji, H. (2009). “Single-Shot Diffractive Imaging with a Table-Top Femtosecond Soft X-Ray Laser-Harmonics Source”, Physical Review Letters, 103, 028104.
Remetter, T., Johnsson, P., Mauritsson, J., Varju, K., Ni, Y., Lepine, F., Gustafsson, E., Kling, M., Khan, J., Lopez-Martens, R., Schafer, K. J., Vrakking, M. J. J., and L'Huillier, A. (2006). “Attosecond electron wave packet interferometry”, Nature Physics, 2, 323-326.
Seaberg, M. D., Adams, D. E., Townsend, E. L., Raymondson, D. A., Schlotter, W. F., Liu, Y., Menoni, C. S., Rong, L., Chen, C.-C., Miao, J., Kapteyn, H. C., and Murnane, M. M. (2011). “Ultrahigh 22 nm resolution coherent diffractive imaging using a desktop 13 nm high harmonic source”, Optics Express, 19, 22470-22479.
Takahashi, E. J., Kanai, T., Ishikawa, K. L., Nabekawa, Y., and Midorikawa, K. (2007). “Dramatic enhancement of high-order harmonic generation”, Physical Review Letters, 99, 053904.
Tate, J. T. and Smith, P. T. (1932). “The Efficiencies of Ionization and Ionization Potentials of Various Gases Under Electron Impact”, Physical Review, 39, 270-277.
Vozzi, C., Calegari, F., Benedetti, E., Berlasso, R., Sansone, G., Stagira, S., Nisoli, M., Altucci, C., Velotta, R., Torres, R., Heesel, E., Kajumba, N., and Marangos, J. P. (2006). “Probing two-centre interference in molecular high harmonic generation”, Journal of Physics B: Atomic, Molecular and Optical Physics, 39, 457-466.