نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه حضرت معصومه(س)، صندوق پستی: 145-37115، قم- ایران

2 پژوهشکده پلاسما و گداخت هسته‌ای، پژوهشگاه علوم و فنون هسته‌ای، سازمان انرژی اتمی ایران، صندوق پستی: 51113-14399، تهران- ایران

چکیده

پلاسماهای لیزری به­‌عنوان یکی از منابع تولید لیزر پرتو ایکس نرم حایز اهمیت می‌باشد. قابلیت کنترل ضریب بهره پرتو خروجی و کیفیت آن از طریق کنترل پارامترهای لیزر و پلاسما از جمله مزیت‌های این روش است. در این پژوهش، یک پالس دمش به‌همراه یک پیش‌­پالس بر روی هدف ژرمانیم به‌عنوان محیط فعال تقویت‌کننده پلاسمایی می‌تابد و بهره لیزر پرتو ایکس نرم در طول‌موج nm 6/19 محاسبه می‌شود. به‌منظور مطالعه اثر پارامترهای لیزری از قبیل شدت، پهنای پالس و اختلاف زمانی بین دو پالس از کد هیدرودینامیکی MED103 استفاده شده است. نتایج شبیه‌سازی نشان می‌دهد که برای دستیابی به بیشینه بهره لیزر پرتو ایکس نرم یک پهنای پالس بهینه برای پیش‌­پالس و نیز پالس اصلی دمش وجود دارد. به‌علاوه مطابق با نتایج به‌دست آمده با افزایش شدت پیش‌­پالس مقدار بهره لیزر پرتو ایکس نرم ابتدا افزایش و سپس کاهش می‌یابد در حالی‌که با افزایش شدت پالس اصلی دمش، این مقدار به­‌طور پیوسته افزایش می‌یابد. ‌هم‌چنین مناطق بهینه مکانی و زمانی بهره لیزر پرتو ایکس نرم در شرایط مختلف اختلاف زمانی دو پالس آورده شده است.

کلیدواژه‌ها

عنوان مقاله [English]

Optimization of pump laser conditions for production of maximum gain of Ne-like Ge soft x-ray laser

نویسندگان [English]

  • G. Ghani Moghadam 1
  • S. Rezaei 2
  • M. J. Jafari 2
  • A. H. Farahbod 2

1 Hazrat-e Masoumeh University, P.O.BOX: 37115-145, Qom, Iran.

2 Plasma and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, P.O.BOX: 14399-51113, Tehran, Iran.

چکیده [English]

Laser produced plasma can be used as the sources of soft X-ray laser. The ability to control the laser quality and its gain coefficient by controlling laser and plasma’s parameters is one of the advantages of this method. In this study, a pump pulse assistant along with a pre-pulse is irradiated on a geranium target as the plasma active medium, thenthe gain of soft X-ray laser at wavelength 19.6 nm is calculated. In order to analyze the effect of laser parameters such as intensity, pulse length, and time delay between two pulses, MED103 hydrodynamic code has been used. The simulation results show that there is optimal pulse duration for the pre-pulse as well as the main pump pulse to achieve the maximum gain of soft X-ray laser. In addition, according to the results, by increasing the pre-pulse intensity the amount of soft X-ray laser gain initially increases and then decreases, while by enhancing the main pulse intensity, it keeps increasing. Also, the optimal spatiotemporal regions of the soft X-ray laser gain for different time delays of two pulses are given.

کلیدواژه‌ها [English]

  • Laser-plasma Interaction
  • Ne-like Ge
  • Soft x-ray laser
  • Plasma active medium
1.    H. Daido, Review of soft x-ray laser researches and developments, Rep. Prog. Phys. 65, 1513-1576 (2002).
 
2.  S. Suckewer and P. Jaegle, X-Ray laser: past, present, and future, Laser Phys. Lett. 6, 411–436 (2009).
 
3.   G. J. Tallents, The physics of soft x-ray lasers pumped by electron collisions in laser plasmas, J. Phys D: Appl. Phys. 36, R259 (2003).
 
4.    B. Rus, et al. Multi-millijoule, deeply saturated x-ray laser at 21.2 nm for applications in plasma physics, Plasma Phys. Control. Fusion 44, B207–B223 (2002).
 
5.  T. ‌Mocek et al. Beam properties of a deeply saturated, half-cavity zinc soft-x-ray laser, J. Opt. Soc. Am. B. 20, 1386 (2003).
 
6.   G. Ghani-Moghadam, A. H. Farahbod, Investigation of self-filtering unstable resonator for soft X-ray lasers, Opt. Commun. 371, 154 (2016).
 
7.     G. Ghani Moghadam and A. H. Farahbod, General formula for calculation of amplified spontaneous emission intensity, Opt. Quant. Electron. 48, 227 (2016).
 
8.     D. L. Matthews et al. Demonstration of a soft x-ray amplifier, Phys. Rev. Lett. 54, 110 (1985).
 
9.     P. Jaegle et al. High gain‐production efficiency and large brightness X‐UV laser at Palaiseau, AIP Conference Proceedings 332, 25 (1995).
 
10.  A. Carillon et al. Saturated and near-diffraction-limited operation of an XUV laser at 23.6 nm, Phys. Rev. Lett. 68, 2917 (1992).
 
11.  J. A. Koch et al. Observation of gain-narrowing and saturation behavior in Se x-ray laser line profiles, Phys. Rev. Lett. 68, 3291 (1992).
 
14.   J. Nilsen and J. C. Moreno, Nearly Monochromatic Lasing at 182 Å in Neonlike Selenium, Phys. Rev. Lett. 74, 3376 (1995).
 
15.  A. Behjat et al. The effects of multi-pulse irradiation on X-ray laser media, Opt. Commun. 135, 49 (1997).
 
16.  E. Oliva et al. Hydrodynamic study of plasma amplifiers for soft-x-ray lasers: A transition in hydrodynamic behavior for plasma columns with widths ranging from 20 μm to 2 mm, Phys. Rev. E. 82, 056408, (2010).
 
17.   J. Dunn et al. Demonstration of x-ray amplification in transient gain nickel-like palladium scheme, Phys. Rev. Lett. 80, 2825 (1998).
 
 
18.   J. Dunn et al. Demonstration of transient gain x-ray lasers near 20 nm for nickellike yttrium, zirconium, niobium, and molybdenum, Opt. Lett. 24, 101 (1999).
 
19.  M. P. Kalachnikov et al. Saturated operation of a transient collisional x-ray laser, Phys. Rev. A 57, 4778 (1998).
 
20.  Y. L. Li et al. Saturated tabletop x-ray laser system at 19 nm, J. Opt. Soc. Am. B 17, 1098 (2000).
 
21.  K. A. Janulewicz et al. Influence of pump pulse parameters on the collisionally pumped germanium X-ray laser in the transient gain regime, Opt. Commun. 168, 183-193 (1999).
 
22.   P. B. Holden et al. A computational investigation of the neon-like germanium collisionally pumped laser, J. Phys. B: At. Mol. Opt. Phys. 27, 341-367 (1994).
 
23.  S. B. Healy et al. Transient high gains at 196 Å produced by picosecond pulse heating of a preformed germanium plasma, Opt. Commun. 132, 442-448 (1996).
 
24.   P. J. Warwick et al. Observation of high transient gain in the germanium x-ray laser at 19.6 nm, J. Opt. Soc. Am. B. 15, 6, 1808-1814 (1998).
 
25.  S. Eliezer, The Interaction of High-Power Lasers with Plasmas, (IOP Publishing Ltd, Philadelphia, 2002).
 
26. P. Gibbon, short pulse laser interactions with matter: An introduction, (Imperical College Press, London, 2005).
 
27.  A. Djaoui and S.J. Rose, Calculation of the time-dependent excitation and ionization in a laser-produced plasma, J. Phys B: At. Mol. Opt. Phys. 25, 2745-2762 (1992).
 
28. A. Djaoui, A user guide for the laser-plasma simulation code: MED103, PAL-TR-96-099 (1996).
 
29.   Y. J. Li, X. Lu, J. Zhang, Effects of delay time on transient Ni-like x-ray lasers, Phys. Rev. E. 66, 046501, (2002).
 
30.   X. Lu, Y. J. Li, J. Zhang, Transient characteristics of a neon-like x-ray laser at 19.6 nm, Physics Of Plasmas, 9, 4, 1412-1415 (2002).
 
31.  X. Lu, Y. J. Li, J. Zhang, Optimization of Drive Pulse Configuration for a High-Gain Transient X-Ray Laser at 19.6 nm, CHIN. PHYS. LETT. 18, 10, 1353 (2001).
 
32.  D. Alessi et al. High repetition rate operation of saturated tabletop soft x-ray lasers in transitions of neon-like ions near 30 nm, Opt. Express, ‌13, 2093 (2005).
 
33. D. Alessi et al. Efficient Excitation of Gain-Saturated Sub-9-nm-Wavelength Tabletop Soft-X-Ray Lasers and Lasing Down to 7.36 nm, Phys. Rev. X. 1, 2, 021023 (2011).
 
34.  G. Ghani Moghadam et al. in: 7th conference on engineering and physics of plasma, (Shahrood University of Technology, Shahrood, Iran, 2019) (In Persian).
 
35. X. Lu et al. Numerical optimization of a picosecond pulse driven Ni-like Nb x-ray laser at 20.3 nm, Physics Of Plasmas, 10, 7, 2978 (2003).