A5042137175- Advanced MEMS and NEMS Technologies
- Electrowetting and Microfluidic Technologies
- Photonic and Optical Devices
- Wireless Power Transfer Systems
- Innovative Energy Harvesting Technologies
- Microfluidic and Capillary Electrophoresis Applications
- Energy Harvesting in Wireless Networks
- Optical Coherence Tomography Applications
- Optical Coatings and Gratings
- Semiconductor Lasers and Optical Devices
- Advanced Surface Polishing Techniques
- Acoustic Wave Resonator Technologies
- Orbital Angular Momentum in Optics
- Advanced MRI Techniques and Applications
- Advanced optical system design
- Mechanical and Optical Resonators
- Advanced Fluorescence Microscopy Techniques
- Modular Robots and Swarm Intelligence
- Advanced Sensor and Energy Harvesting Materials
- Advanced Fiber Optic Sensors
- Adhesion, Friction, and Surface Interactions
- Image Processing Techniques and Applications
- Adaptive optics and wavefront sensing
- Nanofabrication and Lithography Techniques
- Laser Material Processing Techniques
University of Virginia
2003-2024
University of Freiburg
2015-2024
Pennsylvania State University
2023
McCormick (United States)
2019
Bellingham Technical College
2017
Fraunhofer Institute for Microengineering and Microsystems
1998-2016
Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy
2016
Technische Universität Dresden
2014
Heidelberg University
2012
FZI Research Center for Information Technology
1992-2004
This paper focuses on the mechanical properties of polydimethylsiloxane (PDMS) relevant for microelectromechanical system (MEMS) applications. In view limited amount published data, we analyzed two products most commonly used in MEMS, namely RTV 615 from Bayer Silicones and Sylgard 184 Dow Corning. With regard to properties, focused dependence elastic modulus thinner concentration, temperature strain rate. addition, creep thermal aging were analyzed. We conclude that isotropic constant has...
We present a new and accurate method to determine the Poisson's ratio of PDMS, using thermal expansion an optical surface profilometer. The Sylgard 184 was found be ν = 0.4950 ± 0.0010 for 182, 0.4974 0.0006. Furthermore, we that both PDMS types, coefficient depends approximately linearly on curing temperature. This can used almost any kind soft polymer cured from liquid at elevated temperatures.
We report the fabrication of 3D micro coils made with an automatic wire bonder. Using standard MEMS processes such as spin coating and UV lithography on silicon Pyrex® wafers results in high aspect ratio SU-8 posts diameters down to 100 µm that serve mechanical stabilization yokes for coils. The bonder is employed wind 25 insulated gold around arbitrary (e.g. solenoidal) path, yielding arrays Each coil bonded directly on-chip, so loose ends are avoided and, compared other winding methods,...
Beginning with a short historical sketch, electrodynamic energy harvesters focus on vibration generators and volumes below 1dm3 are reviewed. The current challenges to generate up several milliwatts of power from practically relevant flows vibrations addressed, the variety available solutions is sketched. Sixty-seven different harvester concepts more than 130 publications classified respect excitation, additional boundary conditions, design fabrication. A chronological list corresponding...
Automatic wire bonding is a highly mature, cost-efficient and broadly available back-end process, intended to create electrical interconnections in semiconductor chip packaging. Modern production wire-bonding tools can bond wires with speeds of up 30 bonds per second placement accuracies better than , the ability form each individually into desired shape. These features render versatile tool also for integrating applications other interconnections. Wire has been adapted used implement...
Nuclear magnetic resonance spectroscopy (NMR) and imaging (MRI) are important non-destructive investigative techniques for soft matter research. Continuous advancements have not only lead to more sensitive detection, new applications, but also enabled the shrinking of detectable volume sample, a reduction in time needed acquire spectrum or image. At same time, advances microstructuring on-chip laboratories continued unabated. In recent years these two broad areas been productively joined...
In this paper we analyze the capability of adaptive lenses to replace mechanical axial scanning in confocal microscopy. The approach promises achieve high scan rates a rather simple implementation. This may open up new applications biomedical imaging or surface analysis micro- and nanoelectronics, where currently flexibility at process are limiting factors. results show that fast is possible using electrically tunable but performance degrades during scan. due defocus spherical aberrations...
We present a completely revised generation of modular micro-NMR detector, featuring an active sample volume ∼ 100 nL, and improvement 87% in probe efficiency. The detector is capable rapidly screening different samples using exchangeable, application-specific, MEMS-fabricated, microfluidic containers. In contrast to our previous design, the holder chips can be simply sealed with adhesive tape, excellent adhesion due smooth surfaces surrounding fluidic ports, so withstand pressures ∼2.5 bar,...
We present an extended optical characterization of adaptive microfluidic silicone-membrane lens at a wavelength 633 nm, respectively 660 nm. Two different membrane variations; one with homogeneous thickness, and shaped cross section, have been realized. This paper includes the theoretical predictions performance via FEM simulation ray tracing, subsequent orientation dependent experimental analysis quality which is measured MTF setup Mach-Zehnder interferometer. The influence fabrication...
We present for the first time a fully MEMS-integrated technology to manufacture 3D geometrically perfect solenoidal microcoils microscale MRI applications. report 25 µm isotropic resolution MR images of copper sulfate aqueous phantom. These are acquired using with 5 windings insulated diameter Au wire and quality factors as high 46 at operating frequency (400 MHz).
This paper demonstrates a novel quadstable monolithic mechanism (QsMM), which provides four stable equilibrium positions within its planar operation range. The QsMM has been realized from the use of both X- and Y-directional bistable structures, utilize curved snapping beams. Two pairs beams were attached to an inner frame in X Y directions present independent behavior directions. It was found out that design is crucial for quadstability dynamic responses mechanism. A millimeter-scale brass...
We present a lab on chip (LOC) compatible modular platform for magnetic resonance (MR)-based investigation of sub-millimetre samples. The combines the advantages offered respectively by microcoils (high resolution at microscale) and macroscopic surface coils (large field view) as MR-detectors consists phased array (PAMs) providing flat MR-sensitive area 18.3 mm2 with B0-field uniformity better than 0.25 ppm in sensor centre area. demonstrate both high-resolution imaging (MRI) NMR...
In this study, we report on a novel, multi-use, high-resolution NMR/MRI micro-detection probe for the screening of flat samples. It is based Helmholtz coil pair in centre probe, built out two 1.5 mm diameter wirebonded copper coils, resulting homogeneous distribution magnetic field. For liquids and suspensions, custom fabricated, disposable sample inserts are placed inside aligned automatically, preventing sensor samples from contamination. The was successfully tested 500 MHz (11.7 T)...
Global climate change threatens ecosystem functioning worldwide. Forest ecosystems are particularly important for carbon sequestration, thereby buffering and providing socio-economic services. However, recurrent stresses, such as heat waves, droughts floods can affect forests with potential cascading effects on their sink capacity, drought resilience sustainability. Knowledge about the stress impact multitude of processes driving soil-plant-atmosphere interactions within these complex forest...
The shape of liquid interfaces can be precisely controlled using electrowetting, an actuation mechanism which has been widely used for tunable optofluidic micro-optical components such as lenses or irises. We have expanded the considerable flexibility inherent in electrowetting to realize a variable slit, and reconfigurable two-dimensional aperture with no mechanically moving parts. This slit is formed by movement two highly opaque ink droplets. 1.5 mm long aperture, controllably discrete...
Electrically tunable lenses exhibit strong potential for fast motion-free axial scanning in a variety of microscopes. However, they also lead to degradation the achievable resolution because aberrations and misalignment between illumination detection optics that are induced by scan itself. Additionally, typically nonlinear relation actuation voltage displacement leads over- or under-sampled frame acquisition most microscopic techniques their static depth-of-field. To overcome these...
A high NMR detection sensitivity is indispensable when dealing with mass and volume-limited samples, or whenever a spatial resolution required. The use of miniaturised RF coils proven way to increase sensitivity, but may be impractical not applicable every experimental situation. We present the magnetic lenses, denoted as Lenz lenses due their working principle, focus flux macroscopic coil into smaller volume thereby locally enhance experiment - at expense total sensitive volume. Besides...
We present an integrated microfluidic device for on-chip nuclear magnetic resonance (NMR) studies of microscopic samples. The devices are fabricated by means a MEMS compatible process, which joins the automatic wirebond winding solenoidal microcoils and manufacturing complex network using dry-photoresist lamination. wafer-scale cleanroom process is potentially capable mass fabrication. Since non-invasive NMR analysis technique rather insensitive, particularly when sample volumes to be...
Abstract Redox changes in live HeLa cervical cancer cells after doxorubicin treatment can either be analyzed by a novel fluorescence lifetime microscopy (FLIM)‐based redox ratio NAD(P)H‐a2%/FAD‐a1%, called or one of its components (NAD(P)H‐a2%), which is actually driving that and offering simpler alternative metric are both compared. Auto‐fluorescent NAD(P)H, FAD acquired 2‐ photon excitation Tryptophan 3‐photon, at 4 time points up to 60 min demonstrating early drug response doxorubicin....
Abstract Diffraction-limited deep focusing into biological tissue is challenging due to aberrations that lead a broadening of the focal spot. The diffraction limit can be restored by employing aberration correction for example with deformable mirror. However, this results in bulky setup required beam folding. We propose bi-actuator adaptive lens simultaneously enables axial scanning and specimen-induced spherical compact setup. Using confocal microscope, we show diffraction-limited up 340 μm...