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Volume 4, Issue 4 (Suppl)

J Laser Opt Photonics, an open access journal

ISSN: 2469-410X

Optics 2017

November 15-17, 2017

November 15-17, 2017 | Las Vegas, USA

International Conference and Exhibition on

Lasers, Optics & Photonics

Split-and-delay units for soft and hard x-ray free-electron lasers

Sebastian Roling

University of Münster, Germany

n the last decade the development of free-electron lasers (FELs) which operate in the extreme ultraviolet (XUV) and soft and

hard x-ray spectral region have opened this photon energy regime to new and exciting experiments, like single pulse diffractive

imaging, warm dense matter dynamics, surface reactions, the ionization and dissociation dynamics of isolated atoms and molecules

and many more. The duration of the FEL pulses is typically three orders of magnitude shorter than radiation from synchrotrons.

These short pulses of typically a few tens of femtoseconds duration enable the investigation of dynamic processes now also in this

spectral region with its chemically identifying characteristic inner shell excitations. Such studies require the presence of at least two

temporally correlated light pulses. One can employ either one optical pulse from a conventional femtosecond laser and one FEL pulse

or two FEL pulses. The first method has been hampered in the past by timing jitters, although with bunch arrival time measurements

presently the jitter has been reduced to below 100 fs. Pump-probe experiments with x-ray pulses from the FELs alone ask for pulse

splitting devices which in addition delay one pulse against the other. Such devices are usually based on an interferometric concept.

The idea of splitting a light beam and recombining both parts again dates back to the very beginning of the 19th century. The concept

of amplitude beam splitting was first realized in 1881 by A A Michelson in his famous interferometer. It has become a cornerstone for

a large variety of fundamental experiments and instrumentation in the infrared, visible, UV and VUV spectral range. Ten years later

another amplitude splitting interferometer was built independently by L Zehnder and L Mach. This instrument can also be used as

wavefront splitting device. When a pulsed light source like, e.g., a synchrotron or a laser is employed, a different optical path length

in the arms of the interferometer simultaneously implies a temporal delay between the pulses travelling via the different paths. It is

exactly this fundamental principle which turns an interferometer into a pulse split-and-delay unit (SDU). General demands for the

implementation of a SDU at free-electron laser facilities to be considered are: the coverage of a spectral range as broad as practical;

an easy change of the intensity ratio in both beams; a large temporal delay; the preservation of the combined intensity through the

instrument and; a low risk of damage of the optics.

Biography

Sebastian Roling has completed his PhD at the University of Münster, Germany. He works on extreme ultraviolet (XUV) and hard x-ray instrumentation for free-eletron lasers

in the group of Helmut Zacharias at the University of Münster. He is author of more than 20 papers in reputed journals.

s_roli02@uni-muenster.de

Sebastian Roling, J Laser Opt Photonics 2017, 4:4 (Suppl)

DOI: 10.4172/2469-410X-C1-017