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Untersuchung lasererzeugter Plasmen/Röntgenlaser

English title Investigation of laser-produced plasmas/X-ray lasers
Applicant Feurer Thomas
Number 144380
Funding scheme Project funding (Div. I-III)
Research institution Institut für angewandte Physik Universität Bern
Institution of higher education University of Berne - BE
Main discipline Other disciplines of Physics
Start/End 01.10.2012 - 28.02.2017
Approved amount 598'104.00
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Keywords (5)

X-ray lasers; chirped-pulse amplification; laser-produced plasmas; high-peak power lasers; CPA lasers

Lay Summary (English)

Lead
Lay summary

Lasers in the extreme ultraviolet (EUV) and soft-x-ray wavelength range (0.2-30 nm) are expected to have an impact on applica­tions as revolutionary as they did in the visi­ble and infrared (IR) wavelength range. The range of these applications is wide as a result of the inherent properties of x-ray lasers: very high brilliance, short pulse duration, coherence, and short wavelength. The development of lasers in the x-ray spec­tral region is hence of fundamental importance in fields such as micro­sco­py, interferome­try, EUV lithography, surface analysis, photo­electron spectro­sco­py, atomic physics, and plasma physics.

Most of the soft-x-ray lasers demonstrated experimen­tally up to now have used a hot, dense plasma pro­duced by high-power visible or near-IR lasers, in which a population inversion (the prerequisite for lasing action) is created by elec­tron-colli­sio­nal excita­tion. In the past, the high pumping energy required for saturated lasing output has restric­ted the development of x-ray lasers to a few large-scale laser facilities around the world. Reduction of the pumping energy by exploiting novel pumping schemes remains the primary goal in plasma x-ray laser research if these are to become compact laboratory tools, complementary in many respects to free-electron lasers.

Recent progress using the tech­nique of grazing-incidence pumping (GRIP) has lead to saturated x-ray lasing in plas­mas of Ni-like Ag, Pd, Sn, Sb, and Te at wavelengths down to 10.9 nm, some at repetition rates of up to 10 Hz, and for pump energies as low as 2 J. Sub-10-nm lasing has been achieved in Ni-like Ba, La, and Sm with 5-10 J of pumping energy, while simulations predict that ~50 J will be required to generate an x-ray laser in the water win­dow (2.5-4.4 nm).

The primary goal of this project is to extend the range of saturated lasing to wave­lengths well below 10 nm by exploiting and optimizing the GRIP scheme in plasmas pro­duced from targets of Sm, Gd, etc., and possibly other elements of the lanthanide (rare-earth) group. To this end, new target fabrication techniques and/or the use of compound targets, e.g., barium fluoride and lanthanum fluoride, are being developed.

The second goal will be the construction of the compact (table-top) 2-J, few-Hz, Nd:YLF laser based on optical para­metric chirped-pulse amplification (OPCPA). The increased repetition rate is imperative if applications such as EUV lithography and photo­elec­tron spectro­sco­py are envisaged.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Self-photopumped x-ray lasers from elements in the Ne-like and Ni-like ionization state
Siegrist Michael, Staub Felix, Jia Fei, Feurer Thomas, Balmer Juerg, Nilsen Joseph (2017), Self-photopumped x-ray lasers from elements in the Ne-like and Ni-like ionization state, in Optics Communications, 382, 288-293.
Actinic damage of Y/Mo multilayer optics in a table-top plasma-driven x-ray laser
Bleiner Davide (2014), Actinic damage of Y/Mo multilayer optics in a table-top plasma-driven x-ray laser, in Applied Optics, 53(22), 4894-4902.
Analytic study of traveling-wave velocity variation in line-focusing schemes for plasma x-ray lasers
Jia Fei (2014), Analytic study of traveling-wave velocity variation in line-focusing schemes for plasma x-ray lasers, in Applied Optics, 53, 3247-3254.
Sub-10-nm Ni-like Soft-X-Ray Lasers
Jia Fei (2013), Sub-10-nm Ni-like Soft-X-Ray Lasers, in Proc. SPIE 8849, X-Ray Lasers and Coherent X-Ray Sources: Development and Applications X, 884903 , SPIE, Bellingham, Washington.

Collaboration

Group / person Country
Types of collaboration
Lawrence Livermore National Laboratory United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Associated projects

Number Title Start Funding scheme
132690 Untersuchung lasererzeugter Plasmen/Röntgenlaser 01.10.2010 Project funding (Div. I-III)
132690 Untersuchung lasererzeugter Plasmen/Röntgenlaser 01.10.2010 Project funding (Div. I-III)

Abstract

Lasers in the soft-x-ray wavelength range (0.3    30 nm) are expected to have an impact on applica-tions as revolutionary as they did in the visible and infrared wavelength range. The range of these applications is very wide as a result of the inherent properties of x-ray lasers: high brilliance, short pulse duration, coherence, and short wavelength. The development of lasers in the x-ray spec-tral region is hence of fundamental importance in many fields such as holo-graphy, microscopy, interferome-try, x-ray lithography, surface analysis, atomic physics, and plasma physics.
Most of the soft-x-ray lasers demonstrated experimen-tally up to now have used the electron-collisio-nal excitation scheme in a hot, dense laser-produced plasma. Reducing the very high pump energy required for saturated output remains the primary goal in x-ray laser research if these are to become a stan-dard laboratory tool. Using the novel technique of grazing-inci-dence pumping (GRIP), saturated x-ray lasing has recently been demonstrated in plasmas of Ni-like Ag, Pd, and Sn at wavelengths down to 11.9 nm, at repetition rates of up to 10 Hz, and for pump energies as low as 1 J. Simula-tions predict that sub-10-nm lasing should be feasible with 5-10 J of pump energy, and ~100 J would be required to generate an x-ray laser close to the water window (2.5-4.4 nm).
The main goals of the current project are to: i) use the existing CPA laser system to systematically investigate and optimize sub-10-nm x-ray lasing in the grazing-incidence pump-ing(GRIP) geometry, and ii) complete the construction of the compact, 2-J, few-Hz repetition rate, OPCPA/Nd:YLF laser system.
The recent completion of the CPA upgrade of the laser system has resulted in pulse peak powers of up to 10 TW (20 J/2 ps) available for x-ray laser experiments. The main effort will be devoted to the systematic optimization of the travelling-wave excitation (TWE) scheme for x-ray lasing in targets of Ba, La, and Ce at wavelengths of 9.2, 8.8, and 8.5 nm, respectively.
With the TWE scheme optimized, it should be feasible to extend the range of x-ray lasing wavelengths accessible to the GRIP scheme even further into the region below 10 nm. The main candidate for lasing in this region will be Sm at a wavelength of 7.3 nm, as it is the most stable among the rare-earth elements (La, Pr, Sm, Gd, Dy, etc..
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