OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 19 — Sep. 14, 2009
  • pp: 16379–16384
« Show journal navigation

K-shell x-ray emission enhancement via self-guided propagation of intense laser pulses in Ar clusters

Feng Liu, Li-Ming Chen, Xiao-Xuan Lin, Feng Liu, Jing-Long Ma, Run-Ze Li, Yu-Tong Li, Zhao-Hua Wang, Shou-Jun Wang, Zhi-Yi Wei, and Jie Zhang  »View Author Affiliations


Optics Express, Vol. 17, Issue 19, pp. 16379-16384 (2009)
http://dx.doi.org/10.1364/OE.17.016379


View Full Text Article

Acrobat PDF (154 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

K-shell x-ray at about 3 keV emitted from Ar clusters irradiated by 110mJ 55 fs intense laser pulses is studied. The x-ray flux is optimized by moving the nozzle away from the focus of the laser pulse. The total flux of K-shell x-ray photons in 4π reaches a maximum of 4.5×109 photons/shot with a conversion efficiency of 2.5×10−5 when the nozzle displacement is 2 mm and a long plasma channel is observed by a probe beam.

© 2009 OSA

1. Introduction

The intense laser interactions with clusters have been extensively studied because of potential applications including hot electrons ejection [1

1. V. Kumarappan, M. Krishnamurthy, and D. Mathur, “Asymmetric emission of high-energy electrons in the two-dimensional hydrodynamic expansion of large xenon clusters irradiated by intense laser fields,” Phys. Rev. A 67(4), 043204 (2003). [CrossRef]

, 2

2. L. M. Chen, J. J. Park, K. H. Hong, J. L. Kim, J. Zhang, and C. H. Nam, “Emission of a hot electron jet from intense femtosecond-laser-cluster interactions,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 66(2 Pt 2), 025402 (2002). [CrossRef] [PubMed]

], MeV ions generation [3

3. T. Ditmire, E. Springate, J. W. G. Tisch, Y. L. Shao, M. B. Mason, N. Hay, J. P. Marangos, and M. H. R. Hutchinson, “Explosion of atomic clusters heated by high-intensity femtosecond laser pulses,” Phys. Rev. A 57(1), 369–382 (1998). [CrossRef]

], x-ray emission [4

4. A. McPherson, T. S. Luk, B. D. Thompson, A. B. Borisov, O. B. Shiryaev, X. Chen, K. Boyer, and C. K. Rhodes, “Multiphoton induced x-ray emission from Kr clusters on M-shell (~100 Å) and L-shell (~6 Å) transitions,” Phys. Rev. Lett. 72(12), 1810–1813 (1994). [CrossRef] [PubMed]

, 5

5. L. M. Chen, M. Kando, J. Ma, H. Kotaki, Y. Fukuda, Y. Hayashi, I. Daito, T. Homma, K. Ogura, M. Mori, A. S. Pirozhkov, J. Koga, H. Daido, S. V. Bulanov, T. Kimura, T. Tajima, and Y. Kato, “Phase-contrast x-ray imaging with intense Ar Kα radiation from femtosecond-laser-driven gas target,” Appl. Phys. Lett. 90(21), 211501 (2007). [CrossRef]

], and table top laser driven nuclear fusion [6

6. T. Ditmire, J. Zweiback, V. P. Yanovsky, T. E. Cowan, G. Hays, and K. B. Wharton, “Nuclear fusion from explosions of femtosecond laser-heated deuterium clusters,” Nature 398(6727), 489–492 (1999). [CrossRef]

]. Compared to solid target, the x-ray sources from laser driven clusters have the advantage of debris-free and high coupling efficiency of laser energy to the plasmas [7

7. T. Ditmire, R. A. Smith, J. W. G. Tisch, and M. H. R. Hutchinson, “High intensity laser absorption by gases of atomic clusters,” Phys. Rev. Lett. 78(16), 3121–3124 (1997). [CrossRef]

].

It is important to improve the brightness of x-ray source for time resolved diagnostic applications requiring single shot imaging. Laser and cluster parameters have been investigated to enhance the x-ray yields in several experiments [8

8. V. P. Krainov and M. B. Smirnov, “Cluster beams in the super-intense femtosecond laser pulse,” Phys. Rep. 370(3), 237–331 (2002) (and references therein). [CrossRef]

]. It is shown that soft x-ray emission is enhanced by cooling the gas resulting in efficient collisional heating and ionization of larger clusters [9

9. T. Mocek, C. M. Kim, H. J. Shin, D. G. Lee, Y. H. Cha, K. H. Hong, and C. H. Nam, “Enhancement of soft x-ray emission from a cryogenically cooled Ar gas jet irradiated by 25 fs laser pulse,” Appl. Phys. Lett. 76(14), 1819–1821 (2000). [CrossRef]

]. Doped Ar clusters are also used to change the ionization dynamics with easily ionizable H2O molecules to increase K-shell x-ray emission [10

10. J. Jha, D. Mathur, and M. Krishnamurthy, “Enhancement of x-ray yields from heteronuclear cluster plasmas irradiated by intense laser light,” J. Phys. At. Mol. Opt. Phys. 38(18), L291–L299 (2005). [CrossRef]

]. Most of these experiments explore optimization of x-ray emission by altering the interaction dynamics of laser pulses with individual cluster, while only a few results concern on macroscopic effect of laser propagation in clusters [11

11. T. Caillaud, F. Blasco, C. Bonte, F. Dorchies, and P. Mora, “Study of intense femtosecond laser propagation into a dense Ar gas and cluster jet,” Phys. Plasmas 13(3), 033105 (2006). [CrossRef]

].

In this paper, we report the experimental results of K-shell x-ray emission enhancement by self-guided propagation of intense laser pulses in Ar clusters. The total flux of K-shell photons is optimized when plasma channels are created by moving the cluster jet away from the focus of pulses.

2. Experimental setup

The experiment was performed at Institute of Physics, Chinese Academy of Sciences, with the Xtreme Light II (XL-II) Laser system [16

16. J. Zhang, Y. T. Li, Z. M. Sheng, Z. Y. Wei, Q. L. Dong, and X. Lu, “Generation and propagation of hot electrons in laser-plasmas,” Appl. Phys. B 80(8), 957–971 (2005). [CrossRef]

]. Laser energy of 110mJ with duration of 55fs was used to carry out the experiment. The linearly polarized 2TW laser beam at 800 nm is focused on the target by an f/3.5 off-axis parabolic mirror (OAP) to a focal spot with size of 5 μm in FWHM, corresponding to a vacuum peak intensity of 6.6×1018W/cm2.

Figure 1
Fig. 1 Sketch of the experimental setup. The inset shows the dependence of Rayleigh scattered signal S on the gas jet back pressure P. The experimental data is fitted by S∝ P2.44.
shows a sketch of the experimental setup. The main laser pulse propagates along x direction and is focused by the OAP onto the Ar clustering gas jet with back pressure of 4 MPa at z=2mm. The origin of coordinates is defined as when the focus spot of the laser pulse is on the axis of the jet at the output of the nozzle. The spectrum of the x-ray emitted in x direction was measured with a 16 bit single photon counting charge coupled device (LCX CCD, Roper Scientific) [17]. A 30μm thick Be filter in front of the LCX CCD is used to block the x-ray with energy lower than 0.7 keV and the laser light. The energetic electrons accelerated forward are deflected by a magnet to reduce the background x-rays generated by the bremsstrahlung radiation. A probe beam propagates through the plasma in the y direction to get the shadowgraph of the plasma profile.

The clustering gas jet is produced by expanding of high pressure Ar gas out of a conical nozzle with a 3 mm diameter orifice and 1 mm diameter throat. We have characterized the atom density profile of the gas jet with an interferometer. The gas jet density profile at z=2 mm with 4 MPa stagnation pressure is presented in the inset of Fig. 3
Fig. 3 Dependence of the total flux of K-shell photons emitted into 4π on the nozzle position relative to the focus point of laser pulses. The dots are experimental data averaged by 5 shots, and the error bars are standard deviation errors. The inset shows the atom density profile at z=2mm and 4 MPa stagnation pressure.
. The mean size of clusters can be characterized by a parameter Г* introduced by Hegena [18

18. O. F. Hagena, “Cluster ion sources,” Rev. Sci. Instrum. 63(4), 2374–2379 (1992). [CrossRef]

]: Г*=k(d/tan α)0.85P/T2.29, where k is a constant depends on the atom species(k=1650 for Ar), d is the throat diameter in μm, α is the half opening angle of the nozzle (α=8°), P and T is the initial pressure and temperature of the gas before expansion. The mean number of atoms per cluster Ncl scales as: Ncl=100(Г*/1000)1.8 [19

19. F. Dorchies, F. Blasco, T. Caillaud, J. Stevefelt, C. Stenz, A. S. Boldarev, and V. A. Gasilov, “Spatial distribution of cluster size and density insupersonic jets as targets for intense laser pulses,” Phys. Rev. A 68(2), 023201 (2003). [CrossRef]

]. Ncl is estimated to be 2.3×106 and cluster radius is 270 Å for our experimental parameter. The formation of Ar clusters is verified experimentally by Rayleigh scattering as shown in the inset of Fig. 1. The scaling law, S∝P2.44, indicates a gas cluster mixed target.

3. Experimental results and discussion

In order to optimize the x-ray flux, we moved the nozzle away from the focus spot along x direction. The dependence of the total flux of K-shell photons in 4π on the nozzle displacement is shown in Fig. 3. The x-ray flux is low when the laser pulses are focused on the gas jet axis. As the nozzle moves away from the laser focus spot, the x-ray yield is enhanced and reaches its maximum of 4.5×109 photons/shot when the displacement is 2 mm. The conversion efficiency of laser pulse energy to K-shell x-ray is about 2.5×10−5. Our results are comparable to that obtained with a much higher laser power of 100TW [23

23. N. L. Kugland, C. G. Constantin, P. Neumayer, H. K. Chung, A. Collette, E. L. Dewald, D. H. Froula, S. H. Glenzer, A. Kemp, A. L. Kritcher, J. S. Ross, and C. Niemann, “High Kα x-ray conversion efficiency from extended source gas jet targets irradiated by ultra short laser pulses,” Appl. Phys. Lett. 92(24), 241504 (2008). [CrossRef]

]. The x-ray flux will decrease when the distance is increased further.

Transverse shadowgraphs of the plasma when the nozzle is 0, 2.5, and 4 mm away from the laser focus spot are presented in Fig. 4
Fig. 4 Transverse shadowgraphs of the plasma profile when the nozzle is 0 (a), 2.5 mm (b) and 4 mm (c) away from the laser focus. The laser propagates from the right to the left. The focusing cone of the laser pulse in vacuum is marked with white lines in (b) and (c). The position of laser focus is indicated by the arrows. The plasma column and channel is marked by red lines in (a) and (b).
. When the laser is focused on the gas jet axis, a uniform plasma column with diameter of about 360 μm is observed as shown in Fig. 4(a). The intensity of the laser beam is estimated to be 2×1015 W/cm2 corresponding to this diameter. When the displacement is 2.5 mm, a 1.5 mm long plasma channel with diameter of 68 μm is created in Fig. 4(b). The channel length is about 14ZR, where ZR =πw0 2/λ is the Rayleigh length of the laser pulses in vacuum, w0 is the beam waist at the focus obtained in vacuum, λ is the wave length of the laser beam. The intensity of the laser beam inside the channel is estimated to be 5.5×1016 W/cm2. The quivering energy of electrons in this laser fields ε=e2E2/ (2 meω0 2) is 6.5 keV, where e and me is the electron charge and mass, E is laser electric field, and ω0 is the laser angular frequency. This energy is enough to efficiently create inner-shell vacancies by collisions with Ar atoms and ions for the generation of K-shell x-ray [24

24. R. Hippler, K. Saeed, I. Mcgregor, and H. Kleinpoppen, “Energy-dependence of characteristic and bremsstrahlung cross-sections of argon induced by electron-bombardment- at low energies,” Z. Phys. A 307(1), 83–87 (1982). [CrossRef]

].

We believe that the enhancement of the K-shell x-ray emission is due to the self-guided propagation of laser pluses in the long plasma channel. As described by the Hydrodynamic model of the intense laser-cluster interaction proposed by Milchberg et al [25

25. H. M. Milchberg, S. J. McNaught, and E. Parra, “Plasma hydrodynamics of the intense laser-cluster interaction,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 64(5 Pt 2), 056402 (2001). [CrossRef] [PubMed]

], Electrons are ionized and heated by the rising edge of the intense laser pulse. The local electron density inside the cluster increases to supercritical and then decreases to subcritical during the expanding of the nanoplasma. The refractive index of the plasma will increase from 1 to >1 and then decrease to <1 during the cluster pre-heating procedure. So the plasma acts as a convex lens to focus the laser beam and then a concave lens to defocus the laser beam. For low energy laser pulses, long pulse duration [14

14. I. Alexeev, T. M. Antonsen, K. Y. Kim, and H. M. Milchberg, “Self-focusing of intense laser pulses in a clustered gas,” Phys. Rev. Lett. 90(10), 103402 (2003). [CrossRef] [PubMed]

] or a prepulse [15

15. H. H. Chu, H. E. Tsai, Y. F. Xiao, C. H. Lee, J. Y. Lin, J. Wang, S. Y. Chen, and H. E. Chu, “Control of laser-beam propagation and absorption in a nanoplasma gas by programming of a transient complex refractive index with a prepulse,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 69(3 Pt 2), 035403 (2004). [CrossRef] [PubMed]

] is needed to heat the clusters for self-focusing and guided propagation.

3. Conclusions

In conclusion, we have presented K-shell x-ray emission from Ar clusters irradiated by 110mJ 55 fs laser pulses. Emission of K-shell x-ray photons with energy peaked at about 3 keV without a Maxwellian distributed background is obtained. The x-ray flux is optimized by moving the nozzle away from the focal point of the laser pulses. The total flux of K-shell photons emitted into 4π reaches up to 4.5×109 photons/shot and the corresponding conversion efficiency is 2.5×10−5 when the nozzle displacement is 2 mm. The x-ray emission enhancement is correlated with self-guided propagation of intense laser pulses in Ar clusters and a long plasma channel is observed.

Acknowledgments

This work was supported by the NSFC (Grant No. 60878014, 10675164, 60621063, 10735050 and 10734130), National Basic Research Program of China (973 Program) (Grant No. 2007CB815102) and the National High-Tech ICF program.

References and links

1.

V. Kumarappan, M. Krishnamurthy, and D. Mathur, “Asymmetric emission of high-energy electrons in the two-dimensional hydrodynamic expansion of large xenon clusters irradiated by intense laser fields,” Phys. Rev. A 67(4), 043204 (2003). [CrossRef]

2.

L. M. Chen, J. J. Park, K. H. Hong, J. L. Kim, J. Zhang, and C. H. Nam, “Emission of a hot electron jet from intense femtosecond-laser-cluster interactions,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 66(2 Pt 2), 025402 (2002). [CrossRef] [PubMed]

3.

T. Ditmire, E. Springate, J. W. G. Tisch, Y. L. Shao, M. B. Mason, N. Hay, J. P. Marangos, and M. H. R. Hutchinson, “Explosion of atomic clusters heated by high-intensity femtosecond laser pulses,” Phys. Rev. A 57(1), 369–382 (1998). [CrossRef]

4.

A. McPherson, T. S. Luk, B. D. Thompson, A. B. Borisov, O. B. Shiryaev, X. Chen, K. Boyer, and C. K. Rhodes, “Multiphoton induced x-ray emission from Kr clusters on M-shell (~100 Å) and L-shell (~6 Å) transitions,” Phys. Rev. Lett. 72(12), 1810–1813 (1994). [CrossRef] [PubMed]

5.

L. M. Chen, M. Kando, J. Ma, H. Kotaki, Y. Fukuda, Y. Hayashi, I. Daito, T. Homma, K. Ogura, M. Mori, A. S. Pirozhkov, J. Koga, H. Daido, S. V. Bulanov, T. Kimura, T. Tajima, and Y. Kato, “Phase-contrast x-ray imaging with intense Ar Kα radiation from femtosecond-laser-driven gas target,” Appl. Phys. Lett. 90(21), 211501 (2007). [CrossRef]

6.

T. Ditmire, J. Zweiback, V. P. Yanovsky, T. E. Cowan, G. Hays, and K. B. Wharton, “Nuclear fusion from explosions of femtosecond laser-heated deuterium clusters,” Nature 398(6727), 489–492 (1999). [CrossRef]

7.

T. Ditmire, R. A. Smith, J. W. G. Tisch, and M. H. R. Hutchinson, “High intensity laser absorption by gases of atomic clusters,” Phys. Rev. Lett. 78(16), 3121–3124 (1997). [CrossRef]

8.

V. P. Krainov and M. B. Smirnov, “Cluster beams in the super-intense femtosecond laser pulse,” Phys. Rep. 370(3), 237–331 (2002) (and references therein). [CrossRef]

9.

T. Mocek, C. M. Kim, H. J. Shin, D. G. Lee, Y. H. Cha, K. H. Hong, and C. H. Nam, “Enhancement of soft x-ray emission from a cryogenically cooled Ar gas jet irradiated by 25 fs laser pulse,” Appl. Phys. Lett. 76(14), 1819–1821 (2000). [CrossRef]

10.

J. Jha, D. Mathur, and M. Krishnamurthy, “Enhancement of x-ray yields from heteronuclear cluster plasmas irradiated by intense laser light,” J. Phys. At. Mol. Opt. Phys. 38(18), L291–L299 (2005). [CrossRef]

11.

T. Caillaud, F. Blasco, C. Bonte, F. Dorchies, and P. Mora, “Study of intense femtosecond laser propagation into a dense Ar gas and cluster jet,” Phys. Plasmas 13(3), 033105 (2006). [CrossRef]

12.

D. G. Lee, H. T. Kim, K. H. Hong, C. H. Nam, I. W. Choi, A. Bartnik, and H. Fiedorowicz, “Generation of bright low-divergence high-order harmonics in a long gas jet,” Appl. Phys. Lett. 81(20), 3726–3728 (2002). [CrossRef]

13.

M. C. Chou, P. H. Lin, C. A. Lin, J. Y. Lin, J. Wang, and S. Y. Chen, “Dramatic enhancement of optical-field-ionization collisional-excitation x-ray lasing by an optically preformed plasma waveguide,” Phys. Rev. Lett. 99(6), 063904 (2007). [CrossRef] [PubMed]

14.

I. Alexeev, T. M. Antonsen, K. Y. Kim, and H. M. Milchberg, “Self-focusing of intense laser pulses in a clustered gas,” Phys. Rev. Lett. 90(10), 103402 (2003). [CrossRef] [PubMed]

15.

H. H. Chu, H. E. Tsai, Y. F. Xiao, C. H. Lee, J. Y. Lin, J. Wang, S. Y. Chen, and H. E. Chu, “Control of laser-beam propagation and absorption in a nanoplasma gas by programming of a transient complex refractive index with a prepulse,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 69(3 Pt 2), 035403 (2004). [CrossRef] [PubMed]

16.

J. Zhang, Y. T. Li, Z. M. Sheng, Z. Y. Wei, Q. L. Dong, and X. Lu, “Generation and propagation of hot electrons in laser-plasmas,” Appl. Phys. B 80(8), 957–971 (2005). [CrossRef]

17.

http://www.princetoninstruments.com/pdfs/whitepapers/direct_detection.pdf

18.

O. F. Hagena, “Cluster ion sources,” Rev. Sci. Instrum. 63(4), 2374–2379 (1992). [CrossRef]

19.

F. Dorchies, F. Blasco, T. Caillaud, J. Stevefelt, C. Stenz, A. S. Boldarev, and V. A. Gasilov, “Spatial distribution of cluster size and density insupersonic jets as targets for intense laser pulses,” Phys. Rev. A 68(2), 023201 (2003). [CrossRef]

20.

B. X. Hou, J. A. Nees, W. Theobald, G. A. Mourou, L. M. Chen, J. C. Kieffer, A. Krol, and C. C. Chamberlain, “Dependence of hard x-ray yield on laser pulse parameters in the wavelength-cubed regime,” Appl. Phys. Lett. 84(13), 2259–2261 (2004). [CrossRef]

21.

H. S. Park, N. Izumi, M. H. Key, J. A. Koch, O. L. Landen, P. K. Patel, T. W. Phillips, and B. B. Zhang, “Characteristics of high energy Kα and Bremsstrahlung sources generated by short pulse petawatt lasers,” Rev. Sci. Instrum. 75(10), 4048–4050 (2004). [CrossRef]

22.

R. C. Issac, G. Vieux, B. Ersfeld, E. Brunetti, S. P. Jamison, J. Gallacher, D. Clark, and D. A. Jaroszynski, “Ultra hard x rays from krypton clusters heated by intense laser fields,” Phys. Plasmas 11(7), 3491–3496 (2004). [CrossRef]

23.

N. L. Kugland, C. G. Constantin, P. Neumayer, H. K. Chung, A. Collette, E. L. Dewald, D. H. Froula, S. H. Glenzer, A. Kemp, A. L. Kritcher, J. S. Ross, and C. Niemann, “High Kα x-ray conversion efficiency from extended source gas jet targets irradiated by ultra short laser pulses,” Appl. Phys. Lett. 92(24), 241504 (2008). [CrossRef]

24.

R. Hippler, K. Saeed, I. Mcgregor, and H. Kleinpoppen, “Energy-dependence of characteristic and bremsstrahlung cross-sections of argon induced by electron-bombardment- at low energies,” Z. Phys. A 307(1), 83–87 (1982). [CrossRef]

25.

H. M. Milchberg, S. J. McNaught, and E. Parra, “Plasma hydrodynamics of the intense laser-cluster interaction,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 64(5 Pt 2), 056402 (2001). [CrossRef] [PubMed]

26.

F. Dorchies, T. Caillaud, F. Blasco, C. Bonté, H. Jouin, S. Micheau, B. Pons, and J. Stevefelt, “Investigation of laser-irradiated Ar cluster dynamics from K-shell x-ray emission measurements,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 71(6 Pt 2), 066410 (2005). [CrossRef] [PubMed]

ToC Category:
Atomic and Molecular Physics

History
Original Manuscript: July 8, 2009
Revised Manuscript: August 6, 2009
Manuscript Accepted: August 6, 2009
Published: August 31, 2009

Citation
Feng Liu, Li-Ming Chen, Xiao-Xuan Lin, Feng Liu, Jing-Long Ma, Run-Ze Li, Yu-Tong Li, Zhao-Hua Wang, Shou-Jun Wang, Zhi-Yi Wei, and Jie Zhang, "K-shell x-ray emission enhancement via self-guided propagation of intense laser pulses in Ar clusters," Opt. Express 17, 16379-16384 (2009)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-17-19-16379


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. V. Kumarappan, M. Krishnamurthy, and D. Mathur, “Asymmetric emission of high-energy electrons in the two-dimensional hydrodynamic expansion of large xenon clusters irradiated by intense laser fields,” Phys. Rev. A 67(4), 043204 (2003). [CrossRef]
  2. L. M. Chen, J. J. Park, K. H. Hong, J. L. Kim, J. Zhang, and C. H. Nam, “Emission of a hot electron jet from intense femtosecond-laser-cluster interactions,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 66(2 Pt 2), 025402 (2002). [CrossRef] [PubMed]
  3. T. Ditmire, E. Springate, J. W. G. Tisch, Y. L. Shao, M. B. Mason, N. Hay, J. P. Marangos, and M. H. R. Hutchinson, “Explosion of atomic clusters heated by high-intensity femtosecond laser pulses,” Phys. Rev. A 57(1), 369–382 (1998). [CrossRef]
  4. A. McPherson, T. S. Luk, B. D. Thompson, A. B. Borisov, O. B. Shiryaev, X. Chen, K. Boyer, and C. K. Rhodes, “Multiphoton induced x-ray emission from Kr clusters on M-shell (~100 Å) and L-shell (~6 Å) transitions,” Phys. Rev. Lett. 72(12), 1810–1813 (1994). [CrossRef] [PubMed]
  5. L. M. Chen, M. Kando, J. Ma, H. Kotaki, Y. Fukuda, Y. Hayashi, I. Daito, T. Homma, K. Ogura, M. Mori, A. S. Pirozhkov, J. Koga, H. Daido, S. V. Bulanov, T. Kimura, T. Tajima, and Y. Kato, “Phase-contrast x-ray imaging with intense Ar Kα radiation from femtosecond-laser-driven gas target,” Appl. Phys. Lett. 90(21), 211501 (2007). [CrossRef]
  6. T. Ditmire, J. Zweiback, V. P. Yanovsky, T. E. Cowan, G. Hays, and K. B. Wharton, “Nuclear fusion from explosions of femtosecond laser-heated deuterium clusters,” Nature 398(6727), 489–492 (1999). [CrossRef]
  7. T. Ditmire, R. A. Smith, J. W. G. Tisch, and M. H. R. Hutchinson, “High intensity laser absorption by gases of atomic clusters,” Phys. Rev. Lett. 78(16), 3121–3124 (1997). [CrossRef]
  8. V. P. Krainov and M. B. Smirnov, “Cluster beams in the super-intense femtosecond laser pulse,” Phys. Rep. 370(3), 237–331 (2002) (and references therein). [CrossRef]
  9. T. Mocek, C. M. Kim, H. J. Shin, D. G. Lee, Y. H. Cha, K. H. Hong, and C. H. Nam, “Enhancement of soft x-ray emission from a cryogenically cooled Ar gas jet irradiated by 25 fs laser pulse,” Appl. Phys. Lett. 76(14), 1819–1821 (2000). [CrossRef]
  10. J. Jha, D. Mathur, and M. Krishnamurthy, “Enhancement of x-ray yields from heteronuclear cluster plasmas irradiated by intense laser light,” J. Phys. At. Mol. Opt. Phys. 38(18), L291–L299 (2005). [CrossRef]
  11. T. Caillaud, F. Blasco, C. Bonte, F. Dorchies, and P. Mora, “Study of intense femtosecond laser propagation into a dense Ar gas and cluster jet,” Phys. Plasmas 13(3), 033105 (2006). [CrossRef]
  12. D. G. Lee, H. T. Kim, K. H. Hong, C. H. Nam, I. W. Choi, A. Bartnik, and H. Fiedorowicz, “Generation of bright low-divergence high-order harmonics in a long gas jet,” Appl. Phys. Lett. 81(20), 3726–3728 (2002). [CrossRef]
  13. M. C. Chou, P. H. Lin, C. A. Lin, J. Y. Lin, J. Wang, and S. Y. Chen, “Dramatic enhancement of optical-field-ionization collisional-excitation x-ray lasing by an optically preformed plasma waveguide,” Phys. Rev. Lett. 99(6), 063904 (2007). [CrossRef] [PubMed]
  14. I. Alexeev, T. M. Antonsen, K. Y. Kim, and H. M. Milchberg, “Self-focusing of intense laser pulses in a clustered gas,” Phys. Rev. Lett. 90(10), 103402 (2003). [CrossRef] [PubMed]
  15. H. H. Chu, H. E. Tsai, Y. F. Xiao, C. H. Lee, J. Y. Lin, J. Wang, S. Y. Chen, and H. E. Chu, “Control of laser-beam propagation and absorption in a nanoplasma gas by programming of a transient complex refractive index with a prepulse,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 69(3 Pt 2), 035403 (2004). [CrossRef] [PubMed]
  16. J. Zhang, Y. T. Li, Z. M. Sheng, Z. Y. Wei, Q. L. Dong, and X. Lu, “Generation and propagation of hot electrons in laser-plasmas,” Appl. Phys. B 80(8), 957–971 (2005). [CrossRef]
  17. http://www.princetoninstruments.com/pdfs/whitepapers/direct_detection.pdf
  18. O. F. Hagena, “Cluster ion sources,” Rev. Sci. Instrum. 63(4), 2374–2379 (1992). [CrossRef]
  19. F. Dorchies, F. Blasco, T. Caillaud, J. Stevefelt, C. Stenz, A. S. Boldarev, and V. A. Gasilov, “Spatial distribution of cluster size and density insupersonic jets as targets for intense laser pulses,” Phys. Rev. A 68(2), 023201 (2003). [CrossRef]
  20. B. X. Hou, J. A. Nees, W. Theobald, G. A. Mourou, L. M. Chen, J. C. Kieffer, A. Krol, and C. C. Chamberlain, “Dependence of hard x-ray yield on laser pulse parameters in the wavelength-cubed regime,” Appl. Phys. Lett. 84(13), 2259–2261 (2004). [CrossRef]
  21. H. S. Park, N. Izumi, M. H. Key, J. A. Koch, O. L. Landen, P. K. Patel, T. W. Phillips, and B. B. Zhang, “Characteristics of high energy Kα and Bremsstrahlung sources generated by short pulse petawatt lasers,” Rev. Sci. Instrum. 75(10), 4048–4050 (2004). [CrossRef]
  22. R. C. Issac, G. Vieux, B. Ersfeld, E. Brunetti, S. P. Jamison, J. Gallacher, D. Clark, and D. A. Jaroszynski, “Ultra hard x rays from krypton clusters heated by intense laser fields,” Phys. Plasmas 11(7), 3491–3496 (2004). [CrossRef]
  23. N. L. Kugland, C. G. Constantin, P. Neumayer, H. K. Chung, A. Collette, E. L. Dewald, D. H. Froula, S. H. Glenzer, A. Kemp, A. L. Kritcher, J. S. Ross, and C. Niemann, “High Kα x-ray conversion efficiency from extended source gas jet targets irradiated by ultra short laser pulses,” Appl. Phys. Lett. 92(24), 241504 (2008). [CrossRef]
  24. R. Hippler, K. Saeed, I. Mcgregor, and H. Kleinpoppen, “Energy-dependence of characteristic and bremsstrahlung cross-sections of argon induced by electron-bombardment- at low energies,” Z. Phys. A 307(1), 83–87 (1982). [CrossRef]
  25. H. M. Milchberg, S. J. McNaught, and E. Parra, “Plasma hydrodynamics of the intense laser-cluster interaction,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 64(5 Pt 2), 056402 (2001). [CrossRef] [PubMed]
  26. F. Dorchies, T. Caillaud, F. Blasco, C. Bonté, H. Jouin, S. Micheau, B. Pons, and J. Stevefelt, “Investigation of laser-irradiated Ar cluster dynamics from K-shell x-ray emission measurements,” Phys. Rev. E Stat. Nonlin. Soft Matter Phys. 71(6 Pt 2), 066410 (2005). [CrossRef] [PubMed]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

Figures

Fig. 1 Fig. 3 Fig. 2
 
Fig. 4
 

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited