Fully integrated transducer platform with cavity optomechanical readout

Research and development of transducers based on cavity optomechanics is a topic of high interest particularly because these transducers enable measurement of mechanical motion down to the fundamental limit of precision imposed by quantum mechanics. The development of an on-chip cavity optomechanical transducer platform that combines high bandwidth and sensitivity near the standard quantum limit with compactness, robustness, small size, and potential for low cost batch fabrication inherent in MEMS is demonstrated as a proof of concept study. Design, fabrication and characterization of fully integrated and fiber pigtailed transducers is presented. The devices combine high sensitivity (0.14 - 40 fm·Hz^(-1/2), high bandwidth optomechanical readout and built-in thermal and electrostatic actuation. It is implemented by a double-side wafer-scale microfabrication process combining one e-beam, six stepper, and three contact mask aligner lithography steps. The SiN probes can be actuated using an electrical signal supplied to an integrated thermal or electrostatic actuator. The probe is evanescently coupled to a high-Q (10^5 - 2 x 10^6) optical whispering gallery mode of the optical microdisk cavity and the motion is detected by measuring the resonance frequency shift of the optical cavity mode. The actuator can be used to dynamically move the probe as well as to tune the distance between the cantilever and the optical cavity, to change the sensitivity and range of measurement of the cantilever. One side of the probe overhangs the edge of the chip, where it can be easily coupled to a variety of off-chip samples and physical systems of interest. The modular design of the transducer allows for parallelization, which enables the possibility of sensor arrays for simultaneous detection of multiple forces or other physical properties. Parallelization is shown on a 2x1 array, which can be easily extended to larger array architectures. The application of the probe arrays and single probes in a commercial scanning probe microscope is shown. In addition the flexibility of this transducer approach is demonstrated with membrane transducers and acceleration sensors. The performance of all presented transducers is studied, focusing on displacement sensitivity, frequency stability and readout gain tuning.Forschung und Entwicklung von Wandlern basierend auf kavität- optomechanischen Elementen ist ein Forschungsgebiet von hohem Interesse. Sie kombiniert hohe Bandbreiten und Empfindlichkeit nahe dem Standardquantumlimit mit Kompaktheit, Robustheit, kleinen Abmessungen und dem Potential für eine wirtschaftliche Massenproduktion systemimmanent bei mikroelektromechanischen Systemen. Vollintegrierte Wandler erlauben demnach Bewegungsmessungen bis hin zum fundamentalen Quantenlimit. In dieser Arbeit werden Design, Herstellung und Charakterisierung eines vollintegrierten und glasfasergekoppelten Wandlers in einer Machbarkeitsstudie dargestellt. Das System kombiniert hohe Verschiebungsauflösungen 0.14 - 40 fm· Hz^(-1/2), optomechanische Detektion mit hoher Bandbreite und eine eingebaute thermische und elektrostatische Anregung. Die Herstellung erfolgt in einem doppelseitigen mikro- und nanotechnischen Fertigungsverfahren auf Waferbasis, in einer Kombination aus einem Elektronenstrahllithographieschritt, sechs Projektionslithographieschritten und drei Kontaktlithographie Schritten. Die Siliziumnitrid-Sonden können mittels eines elektrischen Signals, angelegt an den integrierten thermischen oder elektrostatischen Aktuator, angeregt werden. Sie sind optisch über das evanecente Feld mit einer optischen Kavität hoher Güte (10^5 - 2 x 10^6) gekoppelt. Die Bewegung der Sonde wird detektiert über eine Veränderung der Resonanzfrequenz der Kavität. Die eingebauten Aktuatoren ermöglichen die Einstellung des Abstandes zwischen Sonde und optischer Kavität, welche die Einstellung der Sensitivität ermöglicht. Eine Seite der Sonde steht über die Kante des Siliziumchips, um die Kopplung mit einer Vielzahl von Proben und physikalischen Systemen zu erlauben. Die modulare Bauweise des Wandlers schafft die Grundlage zur Parallelisierung der Sonden für die gleichzeitige Messung mehrerer Kräfte oder physikalischer Eigenschaften. Die Parallelisierung wird in dieser Arbeit am Beispiel eines 2x1 Array gezeigt, welche mit geringem Aufwand auf größere Arrayarchitekturen angepasst werden kann. Zur Demonstration der Funktion von Einzelsonden und Sondenarrays, wird die Sondenanwendung in der Rasterkraftmikroskopie präsentiert. Des Weiteren wird die Flexibilität der Wandlerbauweise an der Herstellung von Membrane- und Beschleunigungswandlern belegt. Das Verhalten aller hergestellten Wandler wird hinsichtlich der Bewegungsempfindlichkeit, Frequenzstabilität, und Einstellbarkeit der Auslesung analysiert

Psoriasis

This issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of psoriasis

Microcephaly

This issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of microcephaly

On the General Analytical Solution of the Kinematic Cosserat Equations

Based on a Lie symmetry analysis, we construct a closed form solution to the kinematic part of the (partial differential) Cosserat equations describing the mechanical behavior of elastic rods. The solution depends on two arbitrary analytical vector functions and is analytical everywhere except a certain domain of the independent variables in which one of the arbitrary vector functions satisfies a simple explicitly given algebraic relation. As our main theoretical result, in addition to the construction of the solution, we proof its generality. Based on this observation, a hybrid semi-analytical solver for highly viscous two-way coupled fluid-rod problems is developed which allows for the interactive high-fidelity simulations of flagellated microswimmers as a result of a substantial reduction of the numerical stiffness.Comment: 14 pages, 3 figure

Trust in everyday life

Although trust plays a pivotal role in many aspects of life, very little is known about the manifestation of trust and distrust in everyday life. In this work, we integrated several prior approaches to trust and investigated the prevalence and key determinants of trust (vs. distrust) in people’s natural environments, using preregistered experience-sampling methodology. Across more than 4,500 social interactions from a heterogeneous sample of 427 participants, results showed high average levels of trust, but also considerable variability in trust across contexts. This variability was attributable to aspects of trustee perception, social distance, as well as three key dimensions of situational interdependence: conflict of interests, information (un)certainty, and power imbalance. At the dispositional level, average everyday trust was shaped by general trust, moral identity, and zero-sum beliefs. The social scope of most trust-related traits, however, was moderated by social distance: Whereas moral identity buffered against distrusting distant targets, high general distrust and low social value orientation amplified trust differences between close vs. distant others. Furthermore, a laboratory-based trust game predicted everyday trust only with regard to more distant but not close interaction partners. Finally, everyday trust was linked to self-disclosure and to cooperation, particularly in situations of high conflict between interaction partners’ interests. We conclude that trust can be conceptualized as a relational hub that interconnects the social perception of the trustee, the relational closeness between trustor and trustee, key structural features of situational interdependence, and behavioral response options such as self-disclosure

Machbarkeitsstudie Kohleausstieg und nachhaltige Fernwärmeversorgung Berlin 2030

MACHBARKEITSSTUDIE KOHLEAUSSTIEG UND NACHHALTIGE FERNWÄRMEVERSORGUNG BERLIN 2030 Machbarkeitsstudie Kohleausstieg und nachhaltige Fernwärmeversorgung Berlin 2030 / Ritzau, Michael (Rights reserved) ( -

Abnormal Resting-State Network Presence in Females with Overactive Bladder

Overactive bladder (OAB) is a global problem reducing the quality of life of patients and increasing the costs of any healthcare system. The etiology of OAB is understudied but likely involves supraspinal network alterations. Here, we characterized supraspinal resting-state functional connectivity in 12 OAB patients and 12 healthy controls (HC) who were younger than 60 years. Independent component analysis showed that OAB patients had a weaker presence of the salience (Cohen's d = 0.9) and default mode network (Cohen's d = 1.1) and weaker directed connectivity between the fronto-parietal network and salience network with a longer lag time compared to HC. A region of interest analysis demonstrated weaker connectivity in OAB compared to HC (Cohen's d > 1.6 or 1.9). The degree of deviation in supraspinal connectivity in OAB patients (relative to HC) appears to be an indicator of the severity of the lower urinary tract symptoms and an indication that such symptoms are directly related to functional supraspinal alterations. Thus, future OAB therapy options should also consider supraspinal targets, while neuroimaging techniques should be given more consideration in the quest for better phenotyping of OAB