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A current goal for microactuators is to extend their usually small working ranges, which typically result from mechanical connections and restoring forces imposed by cantilevers. In order to overcome this, we present a bistable levitation setup to realise free vertical motion of a magnetic proof mass. By superimposing permanent magnetic fields, we imprint two equilibrium positions, namely on the ground plate and levitating at a predefined height. Energy-efficient switching between both resting positions is achieved by the cooperation of a piezoelectric stack actuator, initially accelerating the proof mass, and subsequent electromagnetic control. A trade-off between robust equilibrium positions and energy-efficient transitions is found by simultaneously optimising the controller and design parameters in a co-design. A flatness-based controller is then proposed for tracking the obtained trajectories. Simulation results demonstrate the effectiveness of the combined optimisation.
Michael Olbrich; Arwed Schütz; Koustav Kanjilal; Tamara Bechtold; Ulrike Wallrabe; Christoph Ament. Co-Design and Control of a Magnetic Microactuator for Freely Moving Platforms. Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications 2020, 64, 23 .
AMA StyleMichael Olbrich, Arwed Schütz, Koustav Kanjilal, Tamara Bechtold, Ulrike Wallrabe, Christoph Ament. Co-Design and Control of a Magnetic Microactuator for Freely Moving Platforms. Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications. 2020; 64 (1):23.
Chicago/Turabian StyleMichael Olbrich; Arwed Schütz; Koustav Kanjilal; Tamara Bechtold; Ulrike Wallrabe; Christoph Ament. 2020. "Co-Design and Control of a Magnetic Microactuator for Freely Moving Platforms." Proceedings of 1st International Electronic Conference on Actuator Technology: Materials, Devices and Applications 64, no. 1: 23.
Recently, the spatio-spectral propagation dynamic of ultrashort-pulsed vortex beams was demonstrated by 2D mapping of spectral moments. The rotation of characteristic anomalies, so-called “spectral eyes”, was explained by wavelength-dependent Gouy phase shift. Controlling of this spectral rotation is essential for specific applications, e.g., communication and processing. Here, we report on advanced concepts for spectral rotational control and related first-proof-of-principle experiments. The speed of rotation of spectral eyes during propagation is shown to be essentially determined by angular and spectral parameters. The performance of fixed diffractive optical elements (DOE) and programmable liquid-crystal-on silicon spatial light modulators (LCoS-SLMs) that act as spiral phase gratings (SPG) or spiral phase plates (SPP) is compared. The approach is extended to radially chirped SPGs inducing axially variable angular velocity. The generation of time-dependent orbital angular momentum (self-torque) by superimposing multiple vortex pulses is proposed.
Max Liebmann; Alexander Treffer; Martin Bock; Ulrike Wallrabe; Ruediger Grunwald. Ultrashort Vortex Pulses with Controlled Spectral Gouy Rotation. Applied Sciences 2020, 10, 4288 .
AMA StyleMax Liebmann, Alexander Treffer, Martin Bock, Ulrike Wallrabe, Ruediger Grunwald. Ultrashort Vortex Pulses with Controlled Spectral Gouy Rotation. Applied Sciences. 2020; 10 (12):4288.
Chicago/Turabian StyleMax Liebmann; Alexander Treffer; Martin Bock; Ulrike Wallrabe; Ruediger Grunwald. 2020. "Ultrashort Vortex Pulses with Controlled Spectral Gouy Rotation." Applied Sciences 10, no. 12: 4288.
We present two piezo-actuated adaptive prisms with apertures of 8 mm based on a bi-axial continuously tiltable glass window on top of an optical fluid, enabling fast scanning applications in a compact, linear axial design. One prism with a device size of 58 by 51 mm is optimized for scan angles of +/-6.4° and response times of 2.5 ms. A second compact prism uses spiral-shaped actuators to achieve a reduced device diameter of 33 mm at slightly compromised maximum scan angles of +/-4.0° with response times of approximately 4 ms. We show the design and FEM-based optimization of the prisms, their fabrication and the characterization of the scan angles and of the dynamic behavior. Finally, we also demonstrate the linearity of the system and discuss a simple control model.
Florian Lemke; Pascal M Weber; Katrin Philipp; Juergen W Czarske; Nektarios Koukourakis; Ulrike Wallrabe; Matthias C Wapler. Piezo-actuated adaptive prisms for continuously adjustable bi-axial scanning. Smart Materials and Structures 2020, 29, 095004 .
AMA StyleFlorian Lemke, Pascal M Weber, Katrin Philipp, Juergen W Czarske, Nektarios Koukourakis, Ulrike Wallrabe, Matthias C Wapler. Piezo-actuated adaptive prisms for continuously adjustable bi-axial scanning. Smart Materials and Structures. 2020; 29 (9):095004.
Chicago/Turabian StyleFlorian Lemke; Pascal M Weber; Katrin Philipp; Juergen W Czarske; Nektarios Koukourakis; Ulrike Wallrabe; Matthias C Wapler. 2020. "Piezo-actuated adaptive prisms for continuously adjustable bi-axial scanning." Smart Materials and Structures 29, no. 9: 095004.
We present the design and fabrication of a miniaturized array of piezoelectrically actuated high speed Fresnel mirrors with individual mirror control. These Fresnel mirrors can be used to generate propagation invariant and self-healing interference patterns. The mirrors are actuated using piezobimorph actuators, and the consequent change of the tilting angle of the mirrors changes the fringe spacing of the interference pattern generated. The array consists of four Fresnel mirrors each having an area of 2x2 mm^2 arranged in a 2x2 configuration. The device, optimized using FEM simulations, is able to achieve maximum mirror deflections of 5 mrad, and has a resonance frequency of 28 kHz.
Binal Poyyathuruthy Bruno; Robert Schütze; Ruediger Grunwald; Ulrike Wallrabe. Micro Fresnel mirror array with individual mirror control. Smart Materials and Structures 2020, 29, 075003 .
AMA StyleBinal Poyyathuruthy Bruno, Robert Schütze, Ruediger Grunwald, Ulrike Wallrabe. Micro Fresnel mirror array with individual mirror control. Smart Materials and Structures. 2020; 29 (7):075003.
Chicago/Turabian StyleBinal Poyyathuruthy Bruno; Robert Schütze; Ruediger Grunwald; Ulrike Wallrabe. 2020. "Micro Fresnel mirror array with individual mirror control." Smart Materials and Structures 29, no. 7: 075003.
Contactless ultrasonic power transmission (UPT) through a metal barrier has become an exciting field of research, as metal barriers prevent the use of electromagnetic wireless power transfer due to Faraday shielding effects. In this paper, we demonstrate power transfer through a metal wall with the use of ultrasonic waves generated from a piezoelectric transducer. Accurate characterization and modeling of the transducer and investigation of the influence of the acoustic properties of the transmitting medium are instrumental for the performance prediction and optimal design of an ultrasonic power link. In this work, we applied the KLM model for the emitting and receiving transducers, with respect to the transmitting medium and model for both the emission and reception function. A practical UPT system was built by mechanically coupling and co-axially aligning two composite transducers on opposite sides of a transmitting medium wall. The optimal transmission performance of the ultrasonic power link through thickness-stretch vibrations of the wall together with two piezoelectric transducers working in TE mode was determined. Eventually, the operating frequency and ohmic loading condition for maximum power transmission were obtained for two different media, aluminium and polyoxymethylene (POM), with contrasting specific acoustic impedances. The results showed that the measured optimal electric loads and operating frequency for maximum power transfer agreed well with the theoretical predictions.
Bibhu Kar; Ulrike Wallrabe. Performance Enhancement of an Ultrasonic Power Transfer System Through a Tightly Coupled Solid Media Using a KLM Model. Micromachines 2020, 11, 355 .
AMA StyleBibhu Kar, Ulrike Wallrabe. Performance Enhancement of an Ultrasonic Power Transfer System Through a Tightly Coupled Solid Media Using a KLM Model. Micromachines. 2020; 11 (4):355.
Chicago/Turabian StyleBibhu Kar; Ulrike Wallrabe. 2020. "Performance Enhancement of an Ultrasonic Power Transfer System Through a Tightly Coupled Solid Media Using a KLM Model." Micromachines 11, no. 4: 355.
We present the design and fabrication of a miniaturized array of piezoelectrically actuated high speed Fresnel mirrors, which can be used to generate propagation invariant and self-healing interference patterns. The mirrors are actuated using piezobimorph actuators, and the consequent change of the tilting angle of the mirrors changes the fringe spacing of the interference pattern generated. The array consists of four Fresnel mirrors each having an area of 2x2 mm2 arranged in a 2x2 configuration. The device, optimized using FEM simulations, is able to achieve maximum mirror deflections of 15 mrad, and has a resonance frequency of 28 kHz.
Binal Poyyathuruthy Bruno; Robert Schütze; Ruediger Grunwald; Ulrike Wallrabe. Piezoelectrically Tunable Micro Fresnel Mirror Array. 2019, 1 .
AMA StyleBinal Poyyathuruthy Bruno, Robert Schütze, Ruediger Grunwald, Ulrike Wallrabe. Piezoelectrically Tunable Micro Fresnel Mirror Array. . 2019; ():1.
Chicago/Turabian StyleBinal Poyyathuruthy Bruno; Robert Schütze; Ruediger Grunwald; Ulrike Wallrabe. 2019. "Piezoelectrically Tunable Micro Fresnel Mirror Array." , no. : 1.
In this paper, we present a finite-element simulation of an adaptive piezoelectric fluid-membrane lens for which we modelled the fluid-structure interaction and resulting membrane deformation in COMSOL Multiphysics®. Our model shows the explicit coupling of the piezoelectric physics with the fluid dynamics physics to simulate the interaction between the piezoelectric and the fluid forces that contribute to the deformation of a flexible membrane in the adaptive lens. Furthermore, the simulation model is extended to describe the membrane deformation by additional fluid forces from the fluid thermal expansion. Subsequently, the simulation model is used to study the refractive power of the adaptive lens as a function of internal fluid pressure and analyze the effect of the fluid thermal expansion on the refractive power. Finally, the simulation results of the refractive power are compared to the experimental results at different actuation levels and temperatures validating the coupled COMSOL model very well. This is explicitly proven by explaining an observed positive drift of the refractive power at higher temperatures.
Hitesh Gowda Bettaswamy Bettaswamy Gowda; Ulrike Wallrabe. Simulation of an Adaptive Fluid-Membrane Piezoelectric Lens. Micromachines 2019, 10, 797 .
AMA StyleHitesh Gowda Bettaswamy Bettaswamy Gowda, Ulrike Wallrabe. Simulation of an Adaptive Fluid-Membrane Piezoelectric Lens. Micromachines. 2019; 10 (12):797.
Chicago/Turabian StyleHitesh Gowda Bettaswamy Bettaswamy Gowda; Ulrike Wallrabe. 2019. "Simulation of an Adaptive Fluid-Membrane Piezoelectric Lens." Micromachines 10, no. 12: 797.
We present two different piezo-actuated adaptive prisms with apertures ≥8 mm based on a tiltable glass window on top of an optical fluid. In the first prism, we realized a simple monoaxial scanner based on a lever principle. In our second design, we extended the scanning to two axes using three individually controllable piezo cantilevers. We were able to prove the concept for continuously adjustable variable prisms and achieved a tilt angle up to ±3.7° with a response time of 36 ms.
Florian Lemke; Pascal M. Weber; Ulrike Wallrabe; Matthias C. Wapler. Piezo-Actuated Adaptive Prisms for Optical Scanning. Springer Proceedings in Physics 2019, 85 -91.
AMA StyleFlorian Lemke, Pascal M. Weber, Ulrike Wallrabe, Matthias C. Wapler. Piezo-Actuated Adaptive Prisms for Optical Scanning. Springer Proceedings in Physics. 2019; ():85-91.
Chicago/Turabian StyleFlorian Lemke; Pascal M. Weber; Ulrike Wallrabe; Matthias C. Wapler. 2019. "Piezo-Actuated Adaptive Prisms for Optical Scanning." Springer Proceedings in Physics , no. : 85-91.
We present a rapid-prototyping process to fabricate aspherical lens arrays based on surface deformation due to thermal expansion of PDMS. Using laser-structuring and molding in combination with an FEM-based shape optimization, we were able to design, fabricate and characterize different micro-lens arrays. This fabrication process can be used for almost any kind of arbitrary lens shape, which allows for a large design freedom for micro lenses.
Angelina Müller; Matthias C. Wapler; Ulrike Wallrabe. Economical rapid-prototyping of aspherical lenses. EPJ Web of Conferences 2019, 215, 04001 .
AMA StyleAngelina Müller, Matthias C. Wapler, Ulrike Wallrabe. Economical rapid-prototyping of aspherical lenses. EPJ Web of Conferences. 2019; 215 ():04001.
Chicago/Turabian StyleAngelina Müller; Matthias C. Wapler; Ulrike Wallrabe. 2019. "Economical rapid-prototyping of aspherical lenses." EPJ Web of Conferences 215, no. : 04001.
Fralett Suarez Sandoval; Sarai M. Torres Delgado; Ali Moazenzadeh; Ulrike Wallrabe. A 2-D Magnetoinductive Wave Device for Freer Wireless Power Transfer. IEEE Transactions on Power Electronics 2019, 34, 10433 -10445.
AMA StyleFralett Suarez Sandoval, Sarai M. Torres Delgado, Ali Moazenzadeh, Ulrike Wallrabe. A 2-D Magnetoinductive Wave Device for Freer Wireless Power Transfer. IEEE Transactions on Power Electronics. 2019; 34 (11):10433-10445.
Chicago/Turabian StyleFralett Suarez Sandoval; Sarai M. Torres Delgado; Ali Moazenzadeh; Ulrike Wallrabe. 2019. "A 2-D Magnetoinductive Wave Device for Freer Wireless Power Transfer." IEEE Transactions on Power Electronics 34, no. 11: 10433-10445.
In this paper we present and verify the non-linear simulation of an aspherical adaptive lens based on a piezo-glass sandwich membrane with combined bending and buckling actuation. To predict the full non-linear piezoelectric behavior, we measured the non-linear charge coefficient, hysteresis and creep effects of the piezo material and inserted them into the FEM model using a virtual electric field. We further included and discussed the fabrication parameters – glue layers and thermal stress – and their variations. To verify our simulations, we fabricated and measured a set of lenses with different geometries, where we found good agreement and show that their qualitative behavior is also well described by a simple analytical model. We finally discuss the effects of the geometry on the electric response and find, e.g., an increased focal power range from ±4.5 to ±9m-1 when changing the aperture from 14 to 10mm
Florian Lemke; Yasmina Frey; Binal Poyyathuruthy Bruno; Katrin Philipp; Nektarios Koukourakis; Jürgen Czarske; Ulrike Wallrabe; Matthias C Wapler; Juergen W Czarske. Multiphysics simulation of the aspherical deformation of piezo-glass membrane lenses including hysteresis, fabrication and nonlinear effects. Smart Materials and Structures 2019, 28, 055024 .
AMA StyleFlorian Lemke, Yasmina Frey, Binal Poyyathuruthy Bruno, Katrin Philipp, Nektarios Koukourakis, Jürgen Czarske, Ulrike Wallrabe, Matthias C Wapler, Juergen W Czarske. Multiphysics simulation of the aspherical deformation of piezo-glass membrane lenses including hysteresis, fabrication and nonlinear effects. Smart Materials and Structures. 2019; 28 (5):055024.
Chicago/Turabian StyleFlorian Lemke; Yasmina Frey; Binal Poyyathuruthy Bruno; Katrin Philipp; Nektarios Koukourakis; Jürgen Czarske; Ulrike Wallrabe; Matthias C Wapler; Juergen W Czarske. 2019. "Multiphysics simulation of the aspherical deformation of piezo-glass membrane lenses including hysteresis, fabrication and nonlinear effects." Smart Materials and Structures 28, no. 5: 055024.
We developed a new and accurate method to determine the Poisson's ratio of PDMS, using thermal expansion and a profilometer.
Angelina Müller; Matthias Christian Wapler; Ulrike Wallrabe. A quick and accurate method to determine the Poisson's ratio and the coefficient of thermal expansion of PDMS. Soft Matter 2018, 15, 779 -784.
AMA StyleAngelina Müller, Matthias Christian Wapler, Ulrike Wallrabe. A quick and accurate method to determine the Poisson's ratio and the coefficient of thermal expansion of PDMS. Soft Matter. 2018; 15 (4):779-784.
Chicago/Turabian StyleAngelina Müller; Matthias Christian Wapler; Ulrike Wallrabe. 2018. "A quick and accurate method to determine the Poisson's ratio and the coefficient of thermal expansion of PDMS." Soft Matter 15, no. 4: 779-784.
In this paper, we compare the performance of 8 PZT ceramics and one PMN-PT material for typical bending actuator applications. This includes the measurement of non-linear transverse charge coefficient at high electric field strength and related quantities such as the Young's modulus, relative permittivity, coercive field and their temperature dependencies, and the Curie temperature. Most materials show much higher strains than what is expected from the datasheet values. We further study the operating region for fields against the polarization direction in different operating cycles and demonstrate a long-term stable quick re-poling method which increases the operating range of negative-only cycles from 50% of Ec to 66% of Ec.
Binal Poyyathuruthy Bruno; Ahmed Raouf Fahmy; Moritz Stürmer; Ulrike Wallrabe; Matthias C Wapler. Properties of piezoceramic materials in high electric field actuator applications. Smart Materials and Structures 2018, 28, 015029 .
AMA StyleBinal Poyyathuruthy Bruno, Ahmed Raouf Fahmy, Moritz Stürmer, Ulrike Wallrabe, Matthias C Wapler. Properties of piezoceramic materials in high electric field actuator applications. Smart Materials and Structures. 2018; 28 (1):015029.
Chicago/Turabian StyleBinal Poyyathuruthy Bruno; Ahmed Raouf Fahmy; Moritz Stürmer; Ulrike Wallrabe; Matthias C Wapler. 2018. "Properties of piezoceramic materials in high electric field actuator applications." Smart Materials and Structures 28, no. 1: 015029.
Among the methods developed for hyperspectral imaging, pushbroom spatial scanning stands out when it comes to achieving high spectral resolution over a wide spectral range. However, conventional pushbroom systems are usually realized using passive system components, which has limited their flexibility and adaptability and narrowed their application scenarios. In this work, we adopt a different approach to the design and construction of pushbroom systems based on using active internal components. We present a new system concept utilizing an internal line scanning unit and a rotating camera mechanism. This enables a dual-mode imaging system that allows switching between 2D spatial imaging and spectral imaging. The line scanning unit, which consists of a narrow slit mounted to a linear piezo motor, facilitates the spatial scanning of the target while eliminating the laborious relative motion between the target and the imaging system, which is needed in conventional spectrographs. A software is developed for the automation and synchronization of the active components, which enables a novel feed-forward compensation function to compensate the shift in the diffraction angle due to the scanning motion of the slit and provide higher flexibility in data acquisition.
Mohammad Abdo; Erik Förster; Patrick Bohnert; Vlad Badilita; Robert Brunner; Ulrike Wallrabe; Jan Korvink. Dual-mode pushbroom hyperspectral imaging using active system components and feed-forward compensation. Review of Scientific Instruments 2018, 89, 083113 .
AMA StyleMohammad Abdo, Erik Förster, Patrick Bohnert, Vlad Badilita, Robert Brunner, Ulrike Wallrabe, Jan Korvink. Dual-mode pushbroom hyperspectral imaging using active system components and feed-forward compensation. Review of Scientific Instruments. 2018; 89 (8):083113.
Chicago/Turabian StyleMohammad Abdo; Erik Förster; Patrick Bohnert; Vlad Badilita; Robert Brunner; Ulrike Wallrabe; Jan Korvink. 2018. "Dual-mode pushbroom hyperspectral imaging using active system components and feed-forward compensation." Review of Scientific Instruments 89, no. 8: 083113.
In this paper, we investigate the suitability of 1-3 composite transducers as receivers in acoustic power transfer applications. In contrast to the commonly used PZT transducers, the composites allow us to modify the acoustic impedance, the losses and the electromechanical coupling factor, and hence analyse their influence on the efficiency of acoustic power receivers. Comparing composite receivers with 40%, 60% and 80% filling factors, we find that the lowest filling fraction gives the highest efficiency. This is due to its lower acoustic mismatch with water, which compensates its lower electromechanical coupling and mechanical quality factor.
M Gorostiaga; M C Wapler; U Wallrabe. Less gives more: on the optimal filling fraction of piezoelectric acoustic power receivers. Journal of Physics: Conference Series 2018, 1052, 012034 .
AMA StyleM Gorostiaga, M C Wapler, U Wallrabe. Less gives more: on the optimal filling fraction of piezoelectric acoustic power receivers. Journal of Physics: Conference Series. 2018; 1052 (1):012034.
Chicago/Turabian StyleM Gorostiaga; M C Wapler; U Wallrabe. 2018. "Less gives more: on the optimal filling fraction of piezoelectric acoustic power receivers." Journal of Physics: Conference Series 1052, no. 1: 012034.
We present the characterization of a circular, 1D wireless power transfer system based on magnetoinductive waves travelling through an array of coupled LC resonators. This work builds upon the linear array that we have introduced in our former publications. The use of high quality double-spiral coils combined with an arrangement of 50% of overlapping between consecutive resonating cells renders low attenuation of the travelling wave. Thus, a receiver device located in the near field of the array is able to be powered from the energy travelling through the array. The newly-introduced flexibility of the array provides an additional degree of freedom for its end-application. We measured unoptimized system efficiencies of up to 60% for 1 mm of radial separation at 13.56 MHz. We present the measurement results of the transfer efficiency between the array and a receiver device for two terminating impedances of the array. We also discuss the feasibility of not implementing an impedance modulation scheme when the receiver device revolves inside the array. It was found that one can obtain small output voltage ripples for rotational frequencies as low as 207 revolutions per minute without a modulation scheme. The system is envisaged to recharge in- and on-body devices whose position cannot be directly controlled. The rotational wireless power transfer system could present an alternative to slip rings which are subjected to mechanical wear.
Fralett Suárez Sandoval; Saraí M. Torres Delgado; Ali Moazenzadeh; Ulrike Wallrabe. Flexible wireless power transfer system based on closed-loop magnetoinductive waveguides: solution to misaligned and rotational systems. Journal of Physics: Conference Series 2018, 1052, 012077 .
AMA StyleFralett Suárez Sandoval, Saraí M. Torres Delgado, Ali Moazenzadeh, Ulrike Wallrabe. Flexible wireless power transfer system based on closed-loop magnetoinductive waveguides: solution to misaligned and rotational systems. Journal of Physics: Conference Series. 2018; 1052 (1):012077.
Chicago/Turabian StyleFralett Suárez Sandoval; Saraí M. Torres Delgado; Ali Moazenzadeh; Ulrike Wallrabe. 2018. "Flexible wireless power transfer system based on closed-loop magnetoinductive waveguides: solution to misaligned and rotational systems." Journal of Physics: Conference Series 1052, no. 1: 012077.
This paper addresses the issue of Joule heating in micromachined inductive suspensions (MIS) and reports a significant decrease of the operating temperature by using a polymer magnetic composite (PMC) core. The PMC material has a high resistivity, thus inhibiting the formation of eddy currents, and a high permeability, thus guiding the magnetic field more efficiently within the MIS structure. We experimentally study the distribution of the PMC material inside the MIS structure and evaluate the effect of the core from the dependence of the levitation height on the excitation current. The experiments carried on in ambient room temperature demonstrate that the temperature inside the micromachined inductive suspension is reduced to 58°C, which is a record-low temperature compared to other MIS structures reported before.
K V Poletkin; Z. Lu; A. Moazenzadeh; S. G. Mariappan; Jan Korvink; U. Wallrabe; V Badilita. Energy-aware 3D micro-machined inductive suspensions with polymer magnetic composite core. Journal of Physics: Conference Series 2018, 1052, 012048 .
AMA StyleK V Poletkin, Z. Lu, A. Moazenzadeh, S. G. Mariappan, Jan Korvink, U. Wallrabe, V Badilita. Energy-aware 3D micro-machined inductive suspensions with polymer magnetic composite core. Journal of Physics: Conference Series. 2018; 1052 (1):012048.
Chicago/Turabian StyleK V Poletkin; Z. Lu; A. Moazenzadeh; S. G. Mariappan; Jan Korvink; U. Wallrabe; V Badilita. 2018. "Energy-aware 3D micro-machined inductive suspensions with polymer magnetic composite core." Journal of Physics: Conference Series 1052, no. 1: 012048.
The paper reports on the reactive ion etching (RIE) and ion beam etching (IBE) of commercially available glasses and their usability for the fabrication of diffractive optical elements as an alternative for expensive quartz glass. Fused quartz, borosilicate glasses BF33, BF40, D263, alkaline‐free aluminoborosilicate glasses AF45 and AF37, and alkaline‐alkaline earth silicate B270 were processed with RIE using CF4/Ar gas mixtures. EDX investigations displayed the dependence of the measured etch rates on non‐volatile reaction products. CF4 /Ar flow rates influence the etch rates which show maximum values in the range of 10 ‐ 20 sccm Ar flow. Etch rates as a function of etch depth were investigated as well. Variations in surface roughness are determined by AFM and SEM investigations. Etch rate, surface roughness and structure shape depend on the alkaline and alkaline earth content of the various glass materials is displayed. The usability of the different glass types regarding optical performance was evaluated by comparison of simulated and measured diffraction efficiencies of ion beam etched (IBE) line gratings, since IBE provides comparable surface qualities. It offers a process alternative for the patterning of micro‐optical elements with high surface quality. Therefore, IBE etch rates were measured as well. This article is protected by copyright. All rights reserved.
Jana Schmitt; Andreas Meier; Ulrike Wallrabe; Friedemann Völklein. Reactive ion etching (CF4/Ar) and ion beam etching of various glasses for diffractive optical element fabrication. International Journal of Applied Glass Science 2018, 9, 499 -509.
AMA StyleJana Schmitt, Andreas Meier, Ulrike Wallrabe, Friedemann Völklein. Reactive ion etching (CF4/Ar) and ion beam etching of various glasses for diffractive optical element fabrication. International Journal of Applied Glass Science. 2018; 9 (4):499-509.
Chicago/Turabian StyleJana Schmitt; Andreas Meier; Ulrike Wallrabe; Friedemann Völklein. 2018. "Reactive ion etching (CF4/Ar) and ion beam etching of various glasses for diffractive optical element fabrication." International Journal of Applied Glass Science 9, no. 4: 499-509.
We present a fluid-membrane lens with two piezoelectric actuators that offer versatile, circular symmetric lens surface shaping. A wavefront-measurement-based control system ensures robustness against creeping and hysteresis effects of the piezoelectric actuators. We apply the adaptive lens to correct synthetic aberrations induced by a deformable mirror. The results suggest that the lens is able to correct spherical aberrations with standard Zernike coefficients between 0 μm and 1 μm, while operating at refractive powers up to about 4m-1. We apply the adaptive lens in a custom-built confocal microscope to allow simultaneous axial scanning and spherical aberration tuning. The confocal microscope is extended by an additional phase measurement system to include the control algorithm. To verify our approach, we use the maximum intensity and the axial FWHM of the overall confocal point spread function as figures of merit. We further discuss the ability of the adaptive lens to correct specimen-induced aberrations in a confocal microscope.
Katrin Philipp; Florian Lemke; Matthias C. Wapler; Nektarios Koukourakis; Ulrike Wallrabe; Jürgen W. Czarske. Axial scanning and spherical aberration correction in confocal microscopy employing an adaptive lens. Optics, Photonics, and Digital Technologies for Imaging Applications V 2018, 10679, 106790E .
AMA StyleKatrin Philipp, Florian Lemke, Matthias C. Wapler, Nektarios Koukourakis, Ulrike Wallrabe, Jürgen W. Czarske. Axial scanning and spherical aberration correction in confocal microscopy employing an adaptive lens. Optics, Photonics, and Digital Technologies for Imaging Applications V. 2018; 10679 ():106790E.
Chicago/Turabian StyleKatrin Philipp; Florian Lemke; Matthias C. Wapler; Nektarios Koukourakis; Ulrike Wallrabe; Jürgen W. Czarske. 2018. "Axial scanning and spherical aberration correction in confocal microscopy employing an adaptive lens." Optics, Photonics, and Digital Technologies for Imaging Applications V 10679, no. : 106790E.
Magnetic resonance‐based detection has a wide range of advantages such as exquisite chemical specificity, the capability to be applied to samples in all states of matter, and a broad range of temperatures, at the same time being a non‐ionizing, nondestructive analytical technique. It suffers, however, from an inherent lack of sensitivity, which becomes even more critical when dealing with small samples, for example, sub‐microliter volumes. Resorting to detectors closely conforming to the “small” samples significantly improves the signal‐to‐noise ratio (SNR) that is being lost by reducing the sample amount, that is, by reducing the available number of spins contributing to the total signal. The tremendous progress of microsystems technologies during the past decades has also been reflected in the way the detectors for magnetic resonance are being designed and built, making possible the advent of the field called “micronuclear magnetic resonance”. The present chapter is aiming at presenting the state of the art in the fabrication of miniaturized detectors for nuclear magnetic resonance, with a focus on the innovation that this field has been enjoying in the recent years.
Jan Korvink; Vlad Badilita; Dario Mager; Oliver Gruschke; Nils Spengler; Shyam Sundar Adhikari Parenky; Ulrike Wallrabe; Markus Meissner. Innovative Coil Fabrication Techniques for Miniaturized Magnetic Resonance Detectors. Micro Energy Harvesting 2018, 109 -141.
AMA StyleJan Korvink, Vlad Badilita, Dario Mager, Oliver Gruschke, Nils Spengler, Shyam Sundar Adhikari Parenky, Ulrike Wallrabe, Markus Meissner. Innovative Coil Fabrication Techniques for Miniaturized Magnetic Resonance Detectors. Micro Energy Harvesting. 2018; ():109-141.
Chicago/Turabian StyleJan Korvink; Vlad Badilita; Dario Mager; Oliver Gruschke; Nils Spengler; Shyam Sundar Adhikari Parenky; Ulrike Wallrabe; Markus Meissner. 2018. "Innovative Coil Fabrication Techniques for Miniaturized Magnetic Resonance Detectors." Micro Energy Harvesting , no. : 109-141.