Publications/Presentations

Johannes Fiedler (UiB) presented a poster in contribution to the 2nd European Quantum Technologies Virtual Conference (EQTC 2021 - https://www.eqtc.org/), on 1 december 2021.   Title: The role of dispersion forces for matter-wave binary holography experiments.   Abstract: Lithography is a commonly applied method to create and manipulate semiconductor devices. A further decrease of the size can currently be reached by using extreme-ultraviolet (EUV) photolithography that uses electromagnetic radiation with a wavelength of 13.5 nm that corresponds to an energy of 92eV [1]. The disadvantage of this method is the high energy transfer from the photons to the wafer. The ability to pattern materials at ever-smaller sizes using photolithography is driving advances in nanotechnology. When the feature size of materials is reduced to the nanoscale, individual atoms and molecules can be manipulated to dramatically alter material properties. Extreme ultraviolet – a next-generation lithography technology – can deliver even pattern sizes down to a few nanometer resolutions. However, the secondary electron blurring from extreme-ultraviolet photons hinders the creation of single-molecule patterns. An alternative approach is the use of matter waves which reaches similar and even much smaller wavelengths with a lower amount of kinetic energy [2]. Lithography with metastable atoms has been suggested as a cost-effective, less-complex alternative to EUV lithography. The great advantage of atom lithography is that the kinetic energy of an atom is much less than that of a photon for a given wavelength. Already in 1995, it was demonstrated experimentally that binary holography can be used to form arbitrary patterns using metastable atoms [2]. In binary holography, a pattern of holes is used to approximate a Fourier transform of the desired target pattern. Recently, it was shown theoretically that binary holography with metastable atoms can in principle be used to form arbitrary patterns with nanometer resolution [3]. However, this publication did not include interaction effects between the mask and the metastable atoms. Here we present an investigation of how the dispersion forces between the atoms and the mask affect the path of the atoms through silicon nitride masks. It was theoretically shown that binary holography with metastable atoms can in principle be used to form arbitrary patterns with nanometer resolution [3]. However, recent experiments and theories on matter-wave diffraction experiments have demonstrated that the dispersion forces play an important role in such systems, leading to a reduction of the transmission area on the one hand [4] and a spatially dependent phase shift imprinted on the matter-wave upon leaving the obstacles on the other hand [5]. Dispersion forces are caused by the ground-state fluctuations of the electromagnetic field which typically result in an attractive force between the constituents.    

Johannes Fiedler (UiB) presented a contribution to the FOMO lecture series (Lectures on Matter-Wave Interferometry) on July 21st 2021. Title: The role of dispersion forces in matter-wave scattering experiments Abstract: Dispersion forces, such as van der Waals forces between neutral particles or Casimir-Polder forces between neutral particles and dielectric surfaces, are caused by the ground-state fluctuations of the electromagnetic field. They can be understood via an exchange of virtual photons that are generated as a dipole response of the particle due to the vacuum fluctuation of the field surrounding it. These resulting forces are weak for large separations and dramatically increase with decreasing distances. To this end, in matter-wave scattering experiments, where the beam particles reach close distances to the diffracted object, which is typical in the order of a few nanometers, these forces dominate the interaction and have a large impact on the experimental results. In this talk, we will shortly introduce these forces and illustrate their impact on the diffraction of particle beams from porous materials. This is of particular relevance for  metastable atom lithography with binary holography masks, currently pursued in the FET-Open project Nanolace.   Link to the abstract: https://www.matterwaveoptics.eu/fomo2021/contributed-talks/fomo2021-abstract/fiedler-johannes-the-role-of-dispersion-forces-in-matter-wave-scattering-experiments/

Veronica Perez (NTNU) presented a contribution to the FOMO lecture series (Lectures on Matter-Wave Interferometry) on July 21st 2021. Title: The NanoLace project: Grid-based holograms for matter waves lithography Abstract: Grid-based binary holography (GBH) is an attractive method for patterning with light or matter waves. It is an approximate technique in which different holographic masks can be used to produce similar patterns. Mask-based pat- tern generation is a critical and costly step in microchip production. The next- generation extreme ultraviolet- (EUV) lithography instruments with a wave- length of 13.5 nm are currently under development. In principle, this should allow patterning down to a resolution of a few nanometers in a single expo- sure. However, lithography with metastable atoms has been suggested as a cost-effective, less-complex alternative to EUV lithography. The great advan- tage of atom lithography is that the kinetic energy of an atom is much less than that of a photon for the same wavelength. Until now, however, no method has been available for making masks for atom lithography that can produce arbitrary, high-resolution patterns; to achieve this is the aim of the NanoLace project. Here we present the resolution that can be achieved when making binary masks to create patterns in a target plane close to the mask with the use of an atom source. Through simulations, we investigate the diffraction and ideal size of the patterns formed by holographic masks using beams of room temperature metastable helium atoms. in an experimental setup. Our calculations are now being extended to consider all experimental key features.   Link to the abstract: https://www.matterwaveoptics.eu/fomo2021/contributed-talks/fomo2021-abstract/simonsen-veronica-p-the-nanolace-project-grid-based-holograms-for-matter-waves-lithography/  

Project Coordinator Bodil Holst presented Nanolace at the Innovation Norway Launch of the Horizon Europe - Pillar III Innovation Europe, which took place as a virtual event on the 9.march 9.00-11.00, with participation of the Norwegian ministers for research and higher education Henrik Aasheim and the minister of Trade and Industry Iselin Nybø   https://www.innovasjonnorge.no/no/tjenester/arrangementer/kick-off-for-horisont-europas-innovasjonspilar/

Coming soon!

Article about Nanolace in Gemini,  a Norwegian magazine on research news published by NTNU and Sintef.   https://gemini.no/2020/06/fremtidens-raskeste-datadingser-kan-fa-norsk-hjelp/

Nanolace is cover story in the Norwegian magazine for professional electronics Elektronikk 11/2019, p. 1-12: Gjennombrudd ved UiB: 1 nanometer i sikte. http://viewer.zmags.com/publication/1a09e128#/1a09e128/1