Complete list of publications

The increasing demand for micro- and nanofabrication and in parallel the increasing requirements on feature size and resolution is leading to an enormous growth in the field of multi-photon three-dimensional fabrication. To enable new and diverse investigations in this field and to enable high precision for nanofabrication on large areas, a high precision positioning system is combined with an ultra-short pulse laser system. The aim is a modular setup with constant adherence to the Abbe-comparator principle in order to achieve systematic improvements in the area of Direct Laser Writing. For a high-quality identification of the microstructures a measurement tool based on atomic force microscopy is used. To enable the fabrication of continuous micro- and nanostructures on large area, an extremely high positioning precision is used, where no further stitching methods are necessary. Therefore as base of the Direct Laser Writing system the nanopositioning and nanomeasuring machine (NMM-1) is used, which was developed at Technische Universität Ilmenau together with SIOS Meßtechnik GmbH, with a positioning volume of 25 mm × 25 mm × 5 mm and a positioning resolution in the sub-nanometer range. First investigations already confirmed that microfabrication with a Femtosecond Laser and the NMM-1 could be realized and showed the possibility of further developments in the field of Direct Laser Writing. Now the modular structure as a research platform is designed in such a way that the various extensions and measurement setups for large-scale investigations can always be implemented in a metrologically traceable manner. The presented work shows the development of a modular functional setup of an exposure system and NMM-1, which enables micro- and nanofabrication and an improvement in the structure size over large areas.

Die Einsatzmöglichkeiten von konventionellen Interferometersystemen sind oft aufgrund ihrer Baugröße eingeschränkt. Weiterhin stellen sie noch immer preisintensive, manuell gefertigte Präzisionsbaugruppen dar. Ihr Einsatz ist daher ökonomisch nur für Nischenanwendungen in der Hochtechnologie gerechtfertigt. Aus diesem Grund wird ein neues kompaktes Mikrointerferometer entwickelt, welches auf dem Michelson-Prinzip basiert. Die gesamte Baugröße dieses Mikrointerferometer beträgt 40 mm x 20 mm x 15 mm. Als Strahlteiler wird eine Strahlteilerplatte verwendet, der nicht auf beiden Seiten parallel ist, sondern einen Keilwinkel hat. Dadurch wird der Interferenzwinkel erzeugt. Außerdem sind beide Seiten mit Polarisationsbeschichtung und Entspiegelungsbeschichtung versehen. Zukünftig können die Beschichtungen auf eine große Platte vorbereitet werden und dann ist eine Massenfertigung für die Strahlteilerplatten möglich, sodass die Herstellungskosten dieser Strahlteilerplatten reduziert werden.

To solve the problem of temperature drift of thermocouples in accelerating rate calorimeter caused by long-term operation, an in-situ calibration method based on multiple fixed-points and Joule heat is proposed in this article. Firstly, the heat transfer model of the calorimeter is established, and the validity of the method is verified by numerical simulation. Secondly, a multiple fixed-points graphite calibrator and a cylindrical electronic resistance element are designed. Finally, the in-situ calibration is carried out. The calibration results show that the maximum permissible measurement error of the sample thermocouple after calibration is better than 0.220 ˚C and that the bias of consistency in-situ calibration method is smaller than 0.110 ˚C. In addition, a di-tert-butyl peroxide in toluene solution with a mass percent of 20% is selected as the experimental sample. The sample experiment results show that the kinetic and thermodynamic parameters are closer to the reference values after thermocouples calibration.

Differing from the conventional peak-to-peak method using two neighboring spectral peaks in the frequency-domain fringe spectrum of the spectral response of a Fabry-Perot etalon to a femtosecond laser, which contains N spectral peaks equally spaced with a spacing of the etalon free spectral range (FSR), the proposed method employs a pair of spectral peaks with a spacing of an integer multiple k (k ≫ 1) of FSR for measurement of the etalon cavity length d with a reduced measurement error. Under the constrain of the total N spectral peaks obtainable in the finite spectral range of the femtosecond laser, the optimized k is identified to be N/2 in consideration of an averaging operation using N - k samples of d to achieve the minimum measurement error. The feasibility of the proposed method is demonstrated by experimental results with an uncertainty analysis based on "Guides to the Expression of Uncertainty in Measurement".

This work describes the use of a compact fiber-interferometric sensor for velocity measurements for the Kibble balance method. Our fiber-interferometric sensor was compared within a Planck-balance setup with a commercial reference interferometer. Results show that the fiber-interferometric sensor is capable of high accuracy velocity measurement comparable with the reference interferometer. High performance and compactness of the sensor head allow it to be integrated into small-size systems, where the use of the conventional interferometer systems is limited or not possible.