NANO OPTICS BERLIN

Neutron Optics

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The company NOB Neutron Optics Berlin GmbH was founded in 2000 as a spin-off from the neutron optics group at the Hahn-Meitner-Institut Berlin, HMI, (now Helmholtz-Zentrum Berlin, HZB) to commercially exploit the accumulated know-how in the field of supermirrors and other neutron optical elements.
The concept of neutron supermirrors was first published by Ferenc Mezei in 1976 [1], [2]. In his group at the HMI Thomas Krist developed since 1986 neutron supermirrors, polarisers and collimators starting with Ni-Ti supermirrors and then polarising FeCo-Si and Fe-Si supermirrors [3].
With these supermirrors, many different devices were realised which are used at the HMI as well as at other research facilities worldwide. The polarising supermirrors were used for reflection and/or transmission polarisers [4], [5], [6], [7]. Later they were used to build solid-state benders in which the neutrons travel inside thin Si wafers which are coated with polarizing and absorbing layers [8]. In the beginning, these benders had the traditional C-shape but since about 2012 the polarisation efficiency of solid state benders was improved to values in the order of 99% by using S-shape benders [9].
The analysing efficiency of a supermirror is limited to an angular divergence in the order of its critical angle. To overcome this limitation, radial benders were built which allow analysing also in the second dimension a wide angular range of neutrons scattered from a line source [10]. The concept of the radial cavity was invented for this purpose [11].
In another development, inversely polarising Co-Cu supermirrors were built for the first time which reflect the spin down instead of the spin up component [12]. Also, solid-state collimators were built for the first time, including collimators with purely absorbing walls as well as with walls coated with a reflecting layer below the absorbing one [13]. This leads to a rectangular transmission function which results in an increased transmission without reducing the resolution. Radial collimators were realised as well [14].

A solid state lens was tested which allows focusing neutron beams [15]. The focusing work was continued with systems of tiny prisms [16], Such systems allow to refocus a neutron beam to the width of a slit at points far away from the focusing systems, e. g. inside a sample. In a different setup they can provide the energy analysis of a small beam. Finally, they can compensate for the effect of gravity at a certain point in space, e. g. for small angle scattering instruments.

In the last two decades NOB provided close to 100 neutron optical systems to most of the neutron reserch facilities worldwide.

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References

[1] F. Mezei, Novel polarized neutron devices: supermirror and spin component amplifier; Communications on Physics 1 (1976) 81.

[2] F. Mezei, P. A. Dagleish, Corrigendum and first experimental evidence on neutron supermirrors; Communications on Physics 2 (1977) 41.

[3] T. Krist, C. Lartigue, F. Mezei: Transmission geometry supermirror neutron polarizer device; Physica B 180 & 181 (1992) 1005-1006.

[4] Th. Krist, C. Pappas, Th. Keller, F. Mezei:The polarizing beam splitter guide at BENSC; Physica B 213 & 214 (1995) 939-941.

[5] Th. Krist, F. Klose, G. P. Felcher: A white beam neutron spin splitter; Physica B 248 (1998) 372-376.

[6] T. Keller, T. Krist, A. Danzig, U. Keiderling, F. Mezei, A. Wiedenmann: The polarized neutron small angle scattering instrument at BENSC Berlin; Nucl. Instr. and Methods in Phys. Res. A 451 (2000) 474-479.

[7] Th. Krist, C. Pappas, A. Teichert, C. Fehr, D. Clemens, E. Steichele and F. Mezei: New polarizing guide for neutron wavelengths above 2.5 Å; J. Phys.: Conf. Ser. 251 (2010) 012081.

[8] Th. Krist, S. J. Kennedy, T. J. Hicks, F. Mezei: New compact neutron polarizer; Physica B 241-243 (1998) 82-85.

[9] Th. Krist, F. Rucker, G. Brandl, R. Georgii: High performance, large cross section S-bender for neutron polarization; Nuclear Inst. and Methods in Physics Research A 698 (2013) 94-97.

[10] Th. Krist, H. Fritzsche, F. Mezei: Large-angle neutron polarisation analyser; Appl. Phys. A 74 [Suppl.] (2002) s221-s223.

[11] Péter Falus, Alexei Vorobiev, Thomas Krist: Test of a two-dimensional neutron spin analyser; Physica B 385-386 (2006) 1149-1151.

[12 ]Th. Krist, J. Hoffmann, P. Schubert-Bischoff, F. Mezei: Inversely polarizing Co-Cu neutron supermirrors; Physica B 241-243 (1998) 86-88.

[13] Th. Krist and F. Mezei: High performance, short solid state collimators with reflecting walls; Nucl. Instr. and Methods in Phys. Res. A 450 (2000) 389-390.

[14] Markus Bleuel, Ed Lang, Thomas Krist, Werner Wagner and Jyotsana Lal: SANSPOL at a Pulsed Source; Physica B 397 (2007) 85-87.

[15]  R. Bartmann, N. Behr, A. Hilger and Th. Krist: New solid state lens for reflective neutron focusing; Nuclear Instruments and Methods in Physics Research A 634 (2011) S104–S107.

[16]  J. Schulz, F. Ott, Ch. Hülsen, Th. Krist: Neutron energy analysis by silicon prisms; Nuclear Inst. and Methods in Physics Research A729 (2013) 334-337J. Schulz, F. Ott, Th. Krist: An improved prism energy analyzer for neutrons; Nuclear Inst. and Methods in Physics Research A744 (2014) 69-72.

 

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X-ray optics

In 2016 NOB started to do research in the field of x-ray optics, supported by several substantial grants, while continuing to produce neutron optics.

In 2018 the company was renamed to NOB Nano Optics Berlin GmbH, emphasizing a common feature of both, neutrons as well as x-ray optics.

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The necessity of new effective and high-resolution diffractive optics became evident in the middle of 2000s years with the developments of methods for the study of ultra-fast material processes with the use of ultra-high time resolution synchrotron radiation (SR) facilities [1, 2], X-ray free-electron lasers (FEL) [3] and laboratory sources, such as high-harmonic generators (HHG) [4] and laser produced plasma sources (LPP) [5]. In the same time, the unique properties of reflective Fresnel optics or reflection zone plates (RZP) have proven to be useful in optical schemes for parallel spectrometers based on scanning electron microscopes (SEM) and electron scanning micro analyzers (ESMA) [6]. In addition to the possibility of Fourier time-energy resolution optimization, a combination of reflection, dispersion, and focusing in a single element increases the transmission efficiency of optical schemes by orders of magnitude, as additional optical elements are not required to produce collimated beams or refocus them as in conventional spectroscopy layouts.

In the last 5 years NOB developed unique advanced technology for the fabrication of RZPs, variable line space (VLS) and conventional diffraction gratings for soft X-rays. In comparison with traditional methods of grating production such as laser interference lithography and mechanical ruling, NOB uses e-beam and laser scanning lithography techniques for pattern generation in combination with vector-scan dry ion etching with high spatial resolution. The production of three-dimensional diffraction structures with varying line space densities exceeding 1000% and line density up to 5000 l/mm with any required diffraction line shape have been produced. The new technology step, fabrication of 3-D diffraction structures on curved substrates, promises considerable improvements for spectrometer and monochromator efficiency, resolution and energy range. Further steps in technology include the replication process of RZP.

In the meantime, specially designed reflection zone plates of different types and configurations were delivered to the University Duisburg-Essen, DESY in Hamburg, Technical University Berlin, Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy in Berlin, ICFO  The Institute of Photonics Sciences, Barcelona, Fritz Haber Institute, Berlin and KIT, Karlsruhe.

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References

[1] K. Holldack, J. Bahrdt, A. Balzer, U. Bovensiepen, M. Brzhezinskaya, A. Erko, A. Eschenlohr, R. Follath, A. Firsov, W. Frentrup, L. Le Guyader, T. Kachel, P. Kuske, R. Mitzner, R. Müller, N. Pontius, T. Quast, I. Radu, J.-S. Schmidt, C. Schüßler-Langeheine, M. Sperling, C. Stamm, C. Trabant and A. Föhlisch, FemtoSpeX: a versatile optical pump-soft X-ray probe facility with 100 fs X-ray pulses of variable polarization, J. Synchrotron Rad. (2014). 21, 1090-1104

[2] Z. Yin, J. Rehanek, H. Löchel, C. Braig, J. Buck, A. Firsov, J. Viefhaus, A. Erko, S. Techert, Highly efficient soft X-ray spectrometer based on a reflection zone plate for resonant inelastic X-ray scattering measurement, Optics Express, (2017), 25(10), 10984-10996

[3] M. Kubin, J. Kern, S. Gul, T. Kroll, R. Chatterjee, H. Löchel, F. D. Fuller, R. G. Sierra, W. Quevedo, C. Weniger, J. Rehanek, A. Firsov, H. Laksmono, C. Weninger, R. Alonso-Mori, D. L. Nordlund, B. Lassalle-Kaiser, J. M. Glownia, J. Krzywinski, S. Moeller, J. J. Turner, M. P. Minitti, G. L. Dakovski, S. Koroidov, A. Kawde, J. S. Kanady, E. Y. Tsui, S. Suseno, Z. Han, E. Hill, T. Taguchi, A. S. Borovik, T. Agapie, J. Messinger, A. Erko, A. Föhlisch, U. Bergmann, R. Mitzner, V. K. Yachandra, J. Yano, P. Wernet, Soft x-ray absorption spectroscopy of metalloproteins and high-valent metal-complexes at room temperature using free-electron lasers, Structural Dynamics (2017), 4, 054307

[4] C. Kleine, M. Ekimova, M.-O. Winghart, S. Eckert, O.Reichel, H. Löchel, J. Probst, C. Braig, C. Seifert, A. Erko, A. Sokolov, M. J. J. Vrakking, E. T. J. Nibbering, and A. Rouzée, Highly Efficient Soft X-ray Spectrometer for Transient Absorption Spectroscopy with Broadband Table-Top High Harmonic Sources, Struct. Dyn. (2021), 8, 034302

[5] I. Mantouvalou, K. Witte, W. Martyanov, A. Jonas, D. Grötzsch, C. Streeck, H. Löchel, I. Rudolph, A. Erko, H. Stiel,  B. Kanngießer, Single shot near edge x-ray absorption fine structure spectroscopy in the laboratory, Appl. Phys. Lett. 108, (2016) 201106

[6] A. Hafner, L. Anklamm, A. Firsov, A. Firsov, H. Löchel, A. Sokolov, R. Gubzhokov, A. Erko, Reflection zone plate wavelength-dispersive spectrometer for ultra-light elements measurements, Optics Express, 23, (23), (2015), 29476

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