@misc{ReifVarlamovaRatzkeetal., author = {Reif, J{\"u}rgen and Varlamova, Olga and Ratzke, Markus and Uhlig, Sebastian}, title = {Laser-Induced Periodic Surface Structures of Thin Complex Multi-Component Films}, series = {Applied Physics / A}, volume = {122}, journal = {Applied Physics / A}, number = {4}, issn = {1432-0630}, doi = {10.1007/s00339-016-9936-7}, pages = {1 -- 6}, language = {en} } @misc{ReifMartensUhligetal., author = {Reif, J{\"u}rgen and Martens, Christian and Uhlig, Sebastian and Ratzke, Markus and Varlamova, Olga and Valette, Stephane and Benayoun, Stephane}, title = {On large area LIPSS coverage by multiple pulses}, series = {Applied Surface Science}, volume = {336}, journal = {Applied Surface Science}, issn = {0169-4332}, doi = {doi:10.1016/j.apsusc.2014.11.153}, pages = {249 -- 254}, language = {en} } @misc{ReifVarlamovaUhligetal., author = {Reif, J{\"u}rgen and Varlamova, Olga and Uhlig, Sebastian and Varlamov, Sergej and Bestehorn, Michael}, title = {On the physics of self-organized nanostructure formation upon femtosecond laser ablation}, series = {Applied Physics A}, volume = {117}, journal = {Applied Physics A}, number = {1}, issn = {0947-8396}, doi = {10.1007/s00339-014-8339-x}, pages = {179 -- 184}, abstract = {We present new results on femtosecond LIPSS on silicon, fostering the dynamic model of self-organized structure formation. The first set of experiments demonstrates LIPSS formation by irradiation with a femtosecond white light continuum. The ripples are, as usual, perpendicular to the light polarization with a fluence-dependent wavelength between 500 and 700 nm. At higher dose (fluence × number of shots), the LIPSS turn to much coarser structures. The second set of experiments displays the dose dependence of pattern evolution at about threshold fluence. In contrast to the general case of multi-pulse LIPSS, where a strong dependence of the structures on the laser polarization is observed, single-shot exposition of silicon at about the ablation threshold results in a concentric pattern of very regular sub-wavelength ripples following the oval shape of the irradiated spot, without any reference to the laser polarization. When increasing the number of pulses, the usual, typical ripples develop and then coalesce into broader perpendicular structures, interlaced with remnants of the first, finer ripples.}, language = {en} } @misc{ConradKaiserGaudetetal., author = {Conrad, Holger and Kaiser, Bert and Gaudet, Matthieu and Langa, Sergiu and Stolz, Michael and Uhlig, Sebastian and Schimmanz, Klaus and Schenk, Harald}, title = {A novel electrostatic actuator class}, series = {Procedia Engineering}, volume = {168}, journal = {Procedia Engineering}, issn = {1877-7058}, doi = {10.1016/j.proeng.2016.11.454}, pages = {1533 -- 1536}, language = {en} } @inproceedings{SchenkConradGaudetetal., author = {Schenk, Harald and Conrad, Holger and Gaudet, Matthieu and Uhlig, Sebastian and Kaiser, Bert and Langa, Sergiu and Stolz, Michael and Schimmanz, Klaus}, title = {A novel electrostatic micro-actuator class and its application potential for optical MEMS}, series = {2016 International Conference on Optical MEMS and Nanophotonics,31 July-04 August 2016, Singapore, proceedings}, booktitle = {2016 International Conference on Optical MEMS and Nanophotonics,31 July-04 August 2016, Singapore, proceedings}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-5090-1036-3}, doi = {10.1109/OMN.2016.7565867}, pages = {Tu 3.11-1 -- Tu 3.11-2}, language = {en} } @inproceedings{GaudetUhligStolzetal., author = {Gaudet, Matthieu and Uhlig, Sebastian and Stolz, Michael and Arscott, S. and Conrad, Holger and Langa, Sergiu and Kaiser, Bert and Schenk, Harald}, title = {Electrostatic bending actuators with liquid filled nanometer scale gap}, series = {MEMS 2017, the 30th IEEE International Conference on Micro Electro Mechanical Systems, Las Vegas, Nevada, USA, January 22-26 2017}, booktitle = {MEMS 2017, the 30th IEEE International Conference on Micro Electro Mechanical Systems, Las Vegas, Nevada, USA, January 22-26 2017}, publisher = {IEEE}, address = {Piscataway, NJ}, isbn = {978-1-5090-5078-9}, pages = {175 -- 178}, language = {en} } @inproceedings{SchenkConradGaudetetal., author = {Schenk, Harald and Conrad, Holger and Gaudet, Matthieu and Uhlig, Sebastian and Kaiser, Bert and Langa, Sergiu and Stolz, Michael and Schimmanz, Klaus}, title = {A contribution to the expansion of the applicability of electrostatic forces in micro transducers}, series = {MOEMS and Miniaturized Systems XVI, 30 January-1 February 2017, San Francisco, California, United States}, booktitle = {MOEMS and Miniaturized Systems XVI, 30 January-1 February 2017, San Francisco, California, United States}, publisher = {SPIE}, address = {Bellingham, Washington, USA}, isbn = {978-1-5106-0674-6}, doi = {10.1117/12.2249575}, language = {en} } @misc{LangaConradKaiseretal., author = {Langa, Sergiu and Conrad, Holger and Kaiser, Bert and Stolz, Michael and Gaudet, Matthieu and Uhlig, Sebastian and Schimmanz, Klaus and Schenk, Harald}, title = {Technological aspects of a new micro-electro-mechanical actuation principle: nano e-drive}, series = {Microsystem Technologies}, volume = {23}, journal = {Microsystem Technologies}, number = {1}, issn = {1432-1858}, doi = {10.1007/s00542-017-3360-6}, pages = {5697 -- 5708}, language = {en} } @misc{BorciaBestehornUhligetal., author = {Borcia, Rodica and Bestehorn, Michael and Uhlig, Sebastian and Gaudet, Matthieu and Schenk, Harald}, title = {Liquid pumping induced by transverse forced vibrations of an elastic beam: A lubrication approach}, series = {Physical Review Fluids}, volume = {3}, journal = {Physical Review Fluids}, number = {8}, issn = {2469-990X}, doi = {10.1103/PhysRevFluids.3.084202}, abstract = {Two liquid pumps are investigated theoretically and numerically: a single thin liquid layer actuated by a periodic force at an elastic beam and a two-layer geometry actuated by an elastic beam. For the second geometry, the beam actuates the liquid from both sides. For both pumps, the liquid film thickness is small compared to the lateral characteristic length of the system. A lubrication theory is developed. The Euler-Bernoulli equation for transverse deformations of an elastic beam is coupled to the fundamental hydrodynamic equations: the Navier-Stokes equation and a continuity equation in the long-wave approximation. In this way, one connects the transverse displacement of the beam with the hydrodynamic quantities (pressure, velocity fields, and flow rates). Appropriate boundary conditions incorporate the function of the valves. The derivation of the theoretical model is followed by numerical simulations. We estimate flow rates (in two and three spatial dimensions) for different system parameters and we compute the efficiency of a well-designed liquid pump.}, language = {en} } @misc{UhligGaudetLangaetal., author = {Uhlig, Sebastian and Gaudet, Matthieu and Langa, Sergiu and Schimmanz, Klaus and Conrad, Holger and Kaiser, Bert and Schenk, Harald}, title = {Electrostatically driven in-plane silicon micropump for modular configuration}, series = {Micromachines}, volume = {9}, journal = {Micromachines}, number = {4}, issn = {2072-666X}, doi = {10.3390/mi9040190}, pages = {15}, abstract = {In this paper, an in-plane reciprocating displacement micropump for liquids and gases which is actuated by a new class of electrostatic bending actuators is reported. The so-called "Nano Electrostatic Drive" is capable of deflecting beyond the electrode gap distance, enabling large generated forces and deflections. Depending on the requirements of the targeted system, the micropump can be modularly designed to meet the specified differential pressures and flow rates by a serial and parallel arrangement of equally working pumping base units. Two selected, medium specific micropump test structure devices for pumping air and isopropanol were designed and investigated. An analytical approach of the driving unit is presented and two-way Fluid-Structure Interaction (FSI) simulations of the micropump were carried out to determine the dynamic behavior. The simulation showed that the test structure device designed for air expected to overcome a total differential pressure of 130 kPa and deliver a flow rate of 0.11 sccm at a 265 Hz driving frequency. The isopropanol design is expected to generate 210 kPa and pump 0.01 sccm at 21 Hz. The device is monolithically fabricated by CMOS-compatible bulk micromachining processes under the use of standard materials only, such as crystalline silicon, silicon dioxide and alumina.}, language = {en} }