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Untersuchung lasererzeugter Plasmen/Röntgenlaser

English title Investigation of laser-produced plasmas/X-ray lasers
Applicant Balmer Jürg E.
Number 121627
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 01.10.2008 - 30.09.2010
Approved amount 510'802.00
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Keywords (7)

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

Lay Summary (English)

Lead
Lay summary
Lasers in the soft-x-ray wavelength range (0.2 nm < l < 30 nm) are expected to have an impact on applications as revolutionary as they did in the visible and infrared wavelength range. The range of these applications is wide as a result of the inherent properties of x-raylasers: 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 many fields such as holography, microscopy, interferometry, x-ray lithography, surface analysis, atomic physics, and plasma physics.Most of the soft-x-ray lasers demonstrated experimentally up to now have used the electroncollisional 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 standard laboratory tool. 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 and Sb at wavelengths down to 11.4 nm, at repetition rates of up to 10 Hz, and for pump energies as low as 2.5 J. Simulations 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) further optimize the GRIP pumping scheme with special emphasis on the pump pulse/amplified pulse velocity mismatch and, ii) start the construction of a compact 2-J, few-Hz repetition-rate Nd:YLF laser system as the pump laser for x-ray lasers in the 10-20 nm region.With the GRIP scheme optimized, it should be feasible to extend the range of x-ray lasing wavelengths to the region below 10 nm and, eventually, into the water window below 4.4 nm.The candidates for lasing in this region will be the rare-earth elements (La, Pr, Sm, Gd, Dy, etc.), and this may require the development of novel target fabrication techniques, i.e., evaporation and handling in inert-gas atmosphere.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

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Associated projects

Number Title Start Funding scheme
132690 Untersuchung lasererzeugter Plasmen/Röntgenlaser 01.10.2010 Project funding (Div. I-III)
113396 Untersuchung lasererzeugter Plasmen/Röntgenlaser 01.10.2006 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-raylasers: 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-colli-sio-nal excita-tion scheme in a hot, dense laser-pro-duced 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) implement a travelling-wave sheme to the existing 300-GW/100-ps CPA (chirped-pulse amplification)Nd:glass laser system and, ii) use the CPA laser system to systematically investigate and optimize sub-10-nm x-ray lasing in the grazing-incidence pump-ing(GRIP) geometry.
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 tar-gets of Pd, Sn, and, Sb at wavelengths of 14.7, 11.9, and 11.4 nm, respec-tively.
With the TWE scheme optimized, it should be feasible to extend the range of x-ray lasing wave-lengths accessible to the GRIP scheme into the region well below 10 nm and, eventually, into the water window below 4.4 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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