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Intense mid-infrared femtosecond radiation for the realization of a coherent soft x-ray source

English title Intense mid-infrared femtosecond radiation for the realization of a coherent soft x-ray source
Applicant Hauri Christoph
Number 128763
Funding scheme R'EQUIP
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Other disciplines of Physics
Start/End 01.02.2010 - 31.01.2011
Approved amount 56'000.00
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Keywords (11)

femtosecond laser system; nonlinear optics; quantum optics; mid-IR laser; few-cycle pulse generation; electric field synthesizer; seeding FEL; high power; high-order; harmonic generation; femtosecond laser source

Lay Summary (English)

Lay summary
The goal of our research is the generation of coherent soft x-rays in the so-called water window (2.3-4.2 nm). In this spectral region the absorption of water gets reduced by about an order of magnitude and enables the application of powerful imaging techniques to biological samples. The availability of the proposed laser would tremendously contribute to new insights into molecular and cell dynamics at an unprecedented spatial resolution. An extension of current state-of the art soft x-ray lasers towards the water window requires the development of novel powerful mid-infrared lasers emitting ultrashort pulses of a few tens of femtoseconds (1 fs = 1e-15 sec) which is an important work package within the frame of this project.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Associated projects

Number Title Start Funding scheme
133840 High power femtosecond amplifier system for THz science,coherent soft x-ray generation, imaging applications and seeding of a Free Electron Laser 01.03.2011 R'EQUIP


We propose the purchase of an optical parametric amplifier system as an add-on to our existing high-intensity laser system in order to push the physical limits of a table-top XUV source towards significantly shorter wavelengths. The requested up-grade is a commercial system (HE-TOPAS, Lightconversion Ltd.) consisting of several nonlinear amplification and frequency conversion stages which allow the production of intense mid-infrared radiation (e.g. ?=2.6 µm) when pumped with a conventional Ti:sapphire amplifier system (?=0.8 µm). The generation of powerful mid-infrared femtosecond pulses opens the door to new and exciting research areas. It allows fundamental studies of nonlinear phenomena driven by intense mid-IR laser such as nonlinear interactions in gases (e.g. filamentation), efficient laser-based THz generation and the generation of high-order harmonics in gases. The availability of such a laser system allows the realization of a table-top coherent soft x-ray source emitting in the water window (e.g. 2.4-4.2 nm). This is an important step towards coherent imaging of living biological tissues. Another important application involves a seeding scheme of the Free Electron Laser currently under construction at PSI for achieving coherent hard x-ray radiation down to 1 nm wavelength range. Only coherent seeding allows the FEL to overcome spontaneous emission and to emit temporally coherent radiation. Seeding helps furthermore to stabilize the FEL pulse energy, spectrum and pulse duration. Many future FEL applications are going to profit from experimental conditions being identical for consecutive shots. Seeding has not been considered for (hard) x-ray FELs due to the lack of appropriate coherent soft x-ray seeding source. With the upgrade of our present laser system we expect to fullfill the requirements of an ideal seeding source.