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Optics Express , Volume 21 , Issue 19 , Page 21728.
Alexander Guggenmos, Roman Rauhut, Michael Hofstetter, Samira Hertrich, Bert Nickel, Jürgen Schmidt, Eric M. Gullikson, Markus Seibald, Wolfgang Schnick, and Ulf Kleineberg.
Ludwig-Maximilians-Universitat Munchen, Fakultat für Physik, Am Coulombwall 1, D-85748 Garching, Germany and
Max-Planck-Institut fur Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching, Germany and
Center for X-Ray Optics, Lawrence Berkeley National Lab 2-400, 1 Cyclotron Road, Berkeley, CA 94720, USA and
Ludwig-Maximilians-Universitat Munchen, Department Chemie, Butenandtstr. 5-13, D-81377 Munchen, Germany.
Abstract
Extending single attosecond pulse technology from currently sub-200 eV to the so called ‘water window’ spectral range may enable for the first time the unique investigation of ultrafast electronic processes within the core states of bio-molecules as proteins or other organic materials. Aperiodic multilayer mirrors serve as key components to shape these attosecond pulses with a high degree of freedom and enable tailored short pulse pump-probe experiments. Here, we report on chirped CrSc multilayer mirrors, fabricated by ion beam deposition with sub-angstrom precision, designed for attosecond pulse shaping in the ‘water window’ spectral range.
© 2013 Optical Society of America.
Additional Information
Attosecond physics has become a branch of physics over the last decades, where attosecond pulses (t=10-18s) are used to probe and control core- and outer shell electron dynamics with unprecedented time resolution. Since no electronically based metrology could ever be fast enough to measure these pulse durations, one has to use a pump (XUV) – probe (IR) measurement technique (attosecond streak camera) to retrieve the temporal intensity shape of the attosecond pulse (XUV) and the vector potential of the driving laser pulse (IR). Both the laser and the XUV beam are focused into the interaction medium by a double mirror (Figure a), where the inner core reflects the attosecond XUV pulse and creates photoelectrons of the investigated matter whereas the outer mirror part reflects the IR. By delaying the pulses to each other one records delay dependent electron energy spectra with a time-of-flight, the streaking spectrogram (Figure b). By means of a multilayer mirror one can shape attosecond pulses with a high degree of freedom (see Optics Express, Vol. 19, Issue 3, pp. 1767-1776, 2011) enabling tailored spectral as well as temporal pulse characteristics. In contrast to the demands on dielectric multilayer mirrors for the visible spectral range, metallic multilayer mirrors for the XUV spectral range consist of a stack of ultrathin nanolayers with near-atomic interface precision. These alternating nanolayers are deposited with <0.01 nm precision by dual ion beam deposition technique fulfilling by their thickness and optical constants the conditions for an intended attosecond pulse. An exemplary TEM cross section image of such a deposited periodic chromium (dark) scandium (bright) multilayer stack is shown in Figure c).
