Diese Forschung wird von der US Defense Advanced Research Projects Agency unter Centers in Integrated Photonics Engineering Research (Cipher) Programm mit Dr. J. Scott Rodgers als Projektleiter gesponsert. Die Informationen in diesem Bericht spiegelt nicht unbedingt die Position oder die Politik der US-Regierung und ohne offizielle Billigung sollte geschlossen werden.

Ein. PDMS Microsphere Vorbereitung (Sphere I) <ol><li> Polydimethylsiloxan (PDMS)-Basis und der Härter werden mit einem Volumenverhältnis von 60:1 vermischt. </li><li> Ein Strang der Kieselsäure optische Faser, etwa 2 cm lang, wird zunächst der Kunststoffverkleidung unter Verwendung eines optischen Stripper gestrippt. </li><li> Ein Ende der Faser erhitzt und gestreckt, um ein Schaftende, das ~ 25-50 um Durchmesser an der Spitze bereitzustellen. </li><li> Die gestreckte Ende der Faser wird in die PDMS-Gemisch durch eine Länge von ungefähr 2-4 mm eingetaucht und dann herausgezogen wird. </li><li> Oberflächenspannung und Gewicht des PDMS-Gemisch ermöglichen zur Bildung einer Kugel an der Spitze des Silica Faser. Die Größe der Kugel wird durch das Eintauchen Länge und Extraktion Geschwindigkeit gesteuert. Durch Variation dieser beiden Parameter, Kugeldurchmesser im Bereich 100 um - 1000 um erhalten werden. </li><li> Mikrokugel / Stengel Anordnung wird dann in einem Ofen bei ~ 90 ° C gelegt 4 h für richtiges Heilen des Poly erlaubenmer Material (zum vernetzten Ketten zu bilden). 1a ist eine schematische Darstellung Sphere I. </li></ol> 2. PDMS-basierte Triple Layer Sphere Vorbereitung (Sphere II) <ol><li> Ein 60:1 PDMS Mikrokugel ist als der innere Kern verwendet. Die gleichen Schritte in 1) oben beschrieben ist für dieses Verfahren gefolgt. </li><li> Eine Mischung aus Bariumtitanat (BaTiO 3) Nanopartikeln und 60:1 PDMS ist als die mittlere Schicht verwendet. Die PDMS-Gemisch, in der gleichen Weise in 1.1 beschrieben) oben hergestellt, wird mit Bariumtitanat Nanopartikeln vermischt. </li><li> Das PDMS Mikrokugel Kern in 2.1 beschrieben) wird dann in der PDMS-Bariumtitanat Mischung zu beschichten (mit einer Schicht Nenndicke von ~ 10 um) getaucht. </li><li> Als nächstes wird der zweischichtige Bereich in einem Ofen bei ~ 90 ° C für 4 Stunden, um eine ordnungsgemäße Aushärten der zweiten Schicht zu ermöglichen platziert. </li><li> Sobald der zweischichtige Bereich gehärtet wird, wird er wieder in einem Gemisch aus 60:1 PDMS, um eine äußere Beschichtung (dritte Schicht) bereitzustellen eingetaucht. Diese äußersteSchicht dient als sphärische optische Führung (~ 10 um Dicke). 1b ist eine schematische Darstellung Sphere II. </li></ol> 3. Silica / PDMS Microsphere Vorbereitung (Sphere III) <ol><li> Ein ~ 3 cm langer Abschnitt einer Kieselsäure Einmodenlichtleitfaser ist ersten seiner Puffer (Kunststoff)-Beschichtung abgestreift und dann seine Spitze wird geschmolzen unter Verwendung eines Mikro-Fackel (zusammen mit dem Mantel und Kern). Oberflächenspannung und Schwerkraft arbeiten zusammen, um das geschmolzene Spitze in einer Kugel formen. Kugeln mit Durchmessern im Bereich von 200 bis 500 um mit diesem Verfahren erhalten werden. </li><li> Das Siliciumdioxid Mikrokugel wird dann in ein Bad aus PDMS Basis eingetaucht (ohne Härtemittel), um es mit einem Mantel von ~ 50 um bedecken. Diese äußere Schicht bleibt als hochviskose Bingham (Yield-Stress) Flüssigkeit. Abbildung 1c ist eine schematische Darstellung Sphere III. </li></ol> 4. Optical Fiber Vorbereitung <ol><li> Ein Abschnitt einer optischen Einmodenfaser ist der Kunststoff cla gestripptdding Verwendung eines optischen Stripper. Verwendung einer Mikro-Fackel die gestreifte Abschnitt der Faser erhitzt, bis sie geschmolzen ist (sowohl die Verkleidung und Faserkern). </li><li> Während der mittlere Abschnitt geschmolzen ist, wird ein Ende der optischen Faser entlang ihrer Achse gezogen, um einen verjüngten Abschnitt der Faser, der etwa 1 cm lang ist auszubilden. Die Dauer des Erhitzens, bestimmen die Ziehgeschwindigkeit und Abstand den Durchmesser des sich verjüngenden Abschnitt, der zwischen 10 und 20 um liegt. Das Licht von dem DFB-Laser in die Kugel durch den verjüngten Abschnitt der Faser gekoppelt. Abbildung 2 zeigt die Kugel-Faserkopplung. </li></ol> 5. Optoelektronische Setup- <ol><li> Der Ausgang eines durchstimmbaren DFB-Laser in eine optische Monomodefaser an einem Ende gekoppelt ist und terminiert mit einer schnellen Photodiode am anderen Ende, wie in Abbildung 3 dargestellt. </li><li> Die Photodiode ausgegeben wird digitalisiert mittels eines Analog-Digital-Wandler (A / D) und auf einem Personal Computer (PC). </li><li&gt; Verwenden eines Mikro-Translationsbühne das Mikrokügelchen (Typ I, II oder III) ist in Kontakt mit dem sich verjüngenden Abschnitt der optischen Faser (2 und 3) gebracht, um eine optische Kopplung zwischen den beiden Elementen bereitstellen. </li><li> Der DFB-Laser wird durch einen Laser-Controller abgestimmt. Der Laser-Controller, der seinerseits durch einen Funktionsgenerator, der eine Sägezahnspannung angetrieben Eingang liefert. </li></ol> 6. Electric Field-Generation <ol><li> Zwei quadratische Messingplatten (2 x 2 cm) mit einer Dicke von 1 mm verwendet werden, um die gleichmäßige elektrische Feld zu erzeugen. Die Platten werden mit einer Spannungsversorgung verbunden ist und die Kugel-Sensoren werden in den Spalt zwischen den beiden Platten (Abbildung 4) gelegt. </li><li> Um die Messempfindlichkeit zu erhöhen, werden die Kugeln zuerst in einem elektrischen Feld von 1 MV / m 2 h gepolt. </li></ol>

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S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain+tunable+high-Q+optical+microsphere+resonator.">Strain tunable high-Q optical microsphere resonator.</a> Optics communications. 145, 86-90 (1998).</li><li>Arnold, S., Khoshsima, M., Teraoka, I., Holler, S., Vollmer, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shift+of+whispering-gallery+modes+in+microspheres+by+protein+adsorption.">Shift of whispering-gallery modes in microspheres by protein adsorption.</a> Optics. 28 (4), 272-274 (2003).</li><li>Rosenberger, A. T., Rezac, J. 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V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wall+shear+stress+sensor+based+on+the+optical+resonances+of+dielectric+microspheres.">Wall shear stress sensor based on the optical resonances of dielectric microspheres.</a> Measurement science and technology. 22, 075203 (2011).</li><li>Ioppolo, T., Ayaz, U. K., &#214;t&#252;gen, M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tuning+of+whispering+gallery+modes+of+spherical+resonators+using+an+external+electric+field.">Tuning of whispering gallery modes of spherical resonators using an external electric field.</a> Optics express. 17 (19), 16465-16479 (2009).</li><li>Ioppolo, T., Stubblefield, J., &#214;t&#252;gen, M. 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Wir haben nichts zu offenbaren.

Die Kugeln sind anfänglich durch Verbinden der Elektroden mit einer Gleichstromquelle Hochspannungsversorgung gepolt. Am Ende der Dauer der Polung sind die Elektrodenzuleitungen von der DC-Spannungsversorgung getrennt und mit einem Funktionsgenerator, wie in 4 angedeutet. Die Ergebnisse in den Figuren 5 bis 8 zeigen, dass positive und negative elektrische Felder (relativ zur Richtung der Polung) zu Sphäre Dehnung und Kompression führen, jeweils dargestellt. Sphere I,...

<table border="1"><tbody><tr><td></td><td> Firma </td><td> Katalog-Nummer </td><td> Kommentare (optional) </td></tr><tr><td> PDMS </td><td> Dow Corning </td><td> Sylgard 184 </td><td></td></tr><tr><td> Quarzglasfaser </td><td> Fiber Instrument Vertrieb </td><td> E-37AP15-FIS </td><td></td></tr><tr><td> Barium-Titanat (BaTiO 3) Nanopartikel </td><td> Sigma Aldrich </td><td> 467.634-100G </td><td></td></tr><tr><td> Laser Controller </td><td> ILX Lightwave </td><td> LDC-3724B </td><td></td></tr><tr><td> DFB Laser </td><td> Agere </td><td> Agere 2300 </td><td> 1,310 um zentrale Wellenlänge </td></tr><tr><td> Photodiode </td><td> Thorlabs </td><td> PDA10CS </td><td></td></tr><tr><td> A / D-Karte </td><td> National Instruments </td><td> PXI 6115 </td><td></td>
 </tr>
 </tbody>
</table>

development of whispering gallery mode polymeric micro-optical electric field sensors

Optischen Moden der dielektrischen Mikrohohlräume haben erhebliche Aufmerksamkeit in den letzten Jahren auf ihr Potential in einem breiten Bereich von Anwendungen. Die optischen Moden werden häufig als &quot;whispering gallery modes&quot; (WGM) oder &quot;Morphologie Resonanzen&quot; (MDR) und eine hohe optische Qualität genannten Faktoren. Einige vorgeschlagene Anwendungen von Mikro-Hohlraum optische Resonatoren sind in der Spektroskopie ein, Mikro-Cavity-Laser-Technologie 2, optische Kommunikation 3-6 sowie Sensor-Technologie. Die WGM-basierten Sensor-Anwendungen schließen diejenigen ein, in der Biologie 7, Spurengaserkennung 8, und Unreinheit Grenzstanderfassung in Flüssigkeiten 9. Mechanische Sensoren auf Basis von Mikrokügelchen Resonatoren sind ebenfalls vorgeschlagen worden, einschließlich solcher für Kraft 10,11, Druck 12, 13 und Beschleunigung Wandschubspannung 14. In der vorliegenden demonstrieren wir einen WGM-basierte elektrische Feld-Sensor, der auf unseren früheren studi bautes 15,16. Ein Kandidat Anwendung dieses Sensors ist bei der Detektion von neuronalen Aktionspotentials. Der elektrische Feldsensor ist an polymeren mehrschichtigen dielektrischen Mikrosphären berechnet. Das äußere elektrische Feld induziert Oberfläche und Körper Kräfte auf den Kugeln (Elektrostriktionseffekt) führenden elastische Verformung. Diese Veränderung in der Morphologie der Kugeln, führt zu Veränderungen in der WGM. Das elektrische Feld induzierte WGM Verschiebungen werden durch Anregen der optischen Moden der Kugeln durch Laserlicht abgefragt. Licht von einer Distributed Feedback (DFB)-Laser (nominalen Wellenlänge von ~ 1,3 um) ist in die Mikrokügelchen mit einem verjüngten Abschnitt einer optischen Einmodenfaser nebeneinander gekoppelt. Das Grundmaterial der Kugeln ist Polydimethylsiloxan (PDMS). Drei Mikrokugel Geometrien verwendet werden: (1) PDMS Kugel mit einem Volumenverhältnis von 60:1 Basis-Härtermischung, (2) Mehrschicht Kugel mit 60:1 PDMS Kern, um die Dielektrizitätskonstante zu erhöhen the Kugel, einer mittleren Schicht von 60:1 PDMS, die mit unterschiedlichen Mengen (2% bis 10% nach Volumen) aus Bariumtitanat und einer äußeren Schicht von 60:1 PDMS und (3) feste Silica Kugel mit einer dünnen Schicht beschichtet gemischt wird von ungehärtetem PDMS Basis. In jeder Art von Sensor wird Laserlicht von dem verjüngten Faser in der äußersten Schicht, die eine hohe optische Qualität Faktor WGM (Q ~ 10 6) bietet gekoppelt. Die Mikrokugeln werden mehrere Stunden bei elektrischen Feldern von ~ 1 MV / m gepolt ihrer Empfindlichkeit gegenüber elektrischen Feldes zu erhöhen.

Optisches Modus (WGM) der Kugel wird durch das Laserlicht angeregt wenn optische Weglänge durch das Licht Paar ist ein ganzzahliges Vielfaches der Wellenlänge des Lasers. Für die Anordnung in Fig. 3 gezeigt, ist die optische Weglänge 2πrn, wobei n und r sind der Brechungsindex und der Radius der Kugel sind. Verwendung geometrischen Optik Näherung ein WGM erfüllt ist, wenn 2πrn = lλ wobei l eine ganze Zahl ist und λ ist der Laser-Wellenl...

Watch this Scientific Journal Video about Development of Whispering Gallery Mode Polymeric Micro-optical Electric Field Sensors at JoVE.com

Development of Whispering Gallery Mode Polymeric Micro-optical Electric Field Sensors

Eine hochempfindliche photonischen Mikrosensor wurde für elektrische Feld Detektion entwickelt. Der Sensor nutzt die optischen Moden eines dielektrischen Kugel. Änderungen in der externen elektrischen Feld stören die Kugel Morphologie, die zu Verschiebungen in seiner optischen Modi. Die elektrische Feldstärke wird durch die Überwachung dieser optischen Verschiebungen gemessen.

Entwicklung von Whispering Gallery-Modus polymeren Mikro-optische Electric Field Sensoren

Optical modes of dielectric micro-cavities have received significant attention in recent years for their potential in a broad range of applications. The ...

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13.0K Aufrufe.  Southern Methodist University. Eine hochempfindliche photonischen Mikrosensor wurde für elektrische Feld Detektion entwickelt. Der Sensor nutzt die optischen Moden eines dielektrischen Kugel. Änderungen in der externen elektrischen Feld stören die Kugel Morphologie, die zu Verschiebungen in seiner optischen Modi. Die elektrische Feldstärke wird durch die Überwachung dieser optischen Verschiebungen gemessen.

Serie: Development of Whispering Gallery Mode Polymeric Micro-optical Electric Field Sensors

Microwave Photonics Systems Based on Whispering-gallery-mode Resonators

Microwave photonics systems rely fundamentally on the interaction between microwave and optical signals. These systems are extremely promising for various areas of technology and applied science, such as aerospace and communication engineering, sensing, metrology, nonlinear photonics, and quantum optics. In this article, we present the principal techniques used in our lab to build microwave photonics systems based on ultra-high Q whispering gallery mode resonators. First detailed in this article is the protocol for resonator polishing, which is based on a grind-and-polish technique close to the ones used to polish optical components such as lenses or telescope mirrors. Then, a white light interferometric profilometer measures surface roughness, which is a key parameter to characterize the quality of the polishing. In order to launch light in the resonator, a tapered silica fiber with diameter in the micrometer range is used. To reach such small diameters, we adopt the "flame-brushing" technique, using simultaneously computer-controlled motors to pull the fiber apart, and a blowtorch to heat the fiber area to be tapered. The resonator and the tapered fiber are later approached to one another to visualize the resonance signal of the whispering gallery modes using a wavelength-scanning laser. By increasing the optical power in the resonator, nonlinear phenomena are triggered until the formation of a Kerr optical frequency comb is observed with a spectrum made of equidistant spectral lines. These Kerr comb spectra have exceptional characteristics that are suitable for several applications in science and technology. We consider the application related to ultra-stable microwave frequency synthesis and demonstrate the generation of a Kerr comb with GHz intermodal frequency.

The customized techniques developed in our lab to build microwave photonics systems based on ultra-high Q whispering gallery mode resonators are presented. The protocols to obtain and characterize these resonators are detailed, and an explanation of some of their applications in microwave photonics is given.

Mikrowelle Photonics Systems on Whispering-Gallery-Mode-Resonatoren Grundlage

Microwave photonics systems rely fundamentally on the interaction between microwave and optical signals. These systems are extremely promising for various ...

Forschung

Ingenieurwesen

Real-Time DC-dynamic Biasing Method for Switching Time Improvement in Severely Underdamped Fringing-field Electrostatic MEMS Actuators

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input bias voltage. However, the tradeoff for the improved switching performance is a relatively long settling time to reach each gap height in response to various applied voltages. Transient applied bias waveforms are employed to facilitate reduced switching times for electrostatic fringing-field MEMS actuators with high mechanical quality factors. Removing the underlying substrate of the fringing-field actuator creates the low mechanical damping environment necessary to effectively test the concept. The removal of the underlying substrate also a has substantial improvement on the reliability performance of the device in regards to failure due to stiction. Although DC-dynamic biasing is useful in improving settling time, the required slew rates for typical MEMS devices may place aggressive requirements on the charge pumps for fully-integrated on-chip designs. Additionally, there may be challenges integrating the substrate removal step into the back-end-of-line commercial CMOS processing steps. Experimental validation of fabricated actuators demonstrates an improvement of 50x in switching time when compared to conventional step biasing results. Compared to theoretical calculations, the experimental results are in good agreement.

The robust device design of fringing-field electrostatic MEMS actuators results in inherently low squeeze-film damping conditions and long settling times when performing switching operations using conventional step biasing. Real-time switching time improvement with DC-dynamic waveforms reduces the settling time of fringing-field MEMS actuators when transitioning between up-to-down and down-to-up states.

Echtzeit-DC-Vorspannung dynamische Verfahren zur Verbesserung Schaltzeit in stark unterdämpft Fransen-Bereich Elektroantriebe MEMS

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input ...

Characterization of Anisotropic Leaky Mode Modulators for Holovideo

Holovideo displays are based on light-bending spatial light modulators. One such spatial light modulator is the anisotropic leaky mode modulator. This modulator is particularly well suited for holographic video experimentation as it is relatively simple and inexpensive to fabricate1-3. Some additional advantages of leaky mode devices include: large aggregate bandwidth, polarization separation of signal light from noise, large angular deflection and frequency control of color1. In order to realize these advantages, it is necessary to be able to adequately characterize these devices as their operation is strongly dependent on waveguide and transducer parameters4. To characterize the modulators, the authors use a commercial prism coupler as well as a custom characterization apparatus to identify guided modes, calculate waveguide thickness and finally to map the device's frequency input and angular output of leaky mode modulators. This work gives a detailed description of the measurement and characterization of leaky mode modulators suitable for full-color holographic video.

This work describes fabrication and characterization of anisotropic leaky mode modulators for holographic video.

Charakterisierung von anisotroper Leaky-Modus Modulatoren für die Holovideo

Holovideo displays are based on light-bending spatial light modulators.  One such spatial light modulator is the anisotropic leaky mode modulator.  This ...

Stimulated Stokes and Antistokes Raman Scattering in Microspherical Whispering Gallery Mode Resonators

Dielectric microspheres can confine light and sound for a length of time through high quality factor whispering gallery modes (WGM). Glass microspheres can be thought as a store of energy with a huge variety of applications: compact laser sources, highly sensitive biochemical sensors and nonlinear phenomena. A protocol for the fabrication of both the microspheres and coupling system is given. The couplers described here are tapered fibers. Efficient generation of nonlinear phenomena related to third order optical non-linear susceptibility &#935;(3) interactions in triply resonant silica microspheres is presented in this paper. The interactions here reported are: Stimulated Raman Scattering (SRS), and four wave mixing processes comprising Stimulated Anti-stokes Raman Scattering (SARS). A proof of the cavity-enhanced phenomenon is given by the lack of correlation among the pump, signal and idler: a resonant mode has to exist in order to obtain the pair of signal and idler. In the case of hyperparametric oscillations (four wave mixing and stimulated anti-stokes Raman scattering), the modes must fulfill the energy and momentum conservation and, last but not least, have a good spatial overlap.

Efficient generation of nonlinear phenomena related to third order optical non-linear susceptibility &#935;(3) interactions in triply resonant silica microspheres is presented in this paper. The interactions here reported are: Stimulated Raman Scattering (SRS), and four wave mixing processes comprising Stimulated Anti-stokes Raman Scattering (SARS).

Stimulated Stokes und Antistokes Raman Scattering in Mikrosphärische Whispering Gallery-Modus Resona

Dielectric microspheres can confine light and sound for a length of time through high quality factor whispering gallery modes (WGM). Glass microspheres ...

Fiber Optic Distributed Sensors for High-resolution Temperature Field Mapping

The reliability of computational fluid dynamics (CFD) codes is checked by comparing simulations with experimental data. A typical data set consists chiefly of velocity and temperature readings, both ideally having high spatial and temporal resolution to facilitate rigorous code validation. While high resolution velocity data is readily obtained through optical measurement techniques such as particle image velocimetry, it has proven difficult to obtain temperature data with similar resolution. Traditional sensors such as thermocouples cannot fill this role, but the recent development of distributed sensing based on Rayleigh scattering and swept-wave interferometry offers resolution suitable for CFD code validation work. Thousands of temperature measurements can be generated along a single thin optical fiber at hundreds of Hertz. Sensors function over large temperature ranges and within opaque fluids where optical techniques are unsuitable. But this type of sensor is sensitive to strain and humidity as well as temperature and so accuracy is affected by handling, vibration, and shifts in relative humidity. Such behavior is quite unlike traditional sensors and so unconventional installation and operating procedures are necessary to ensure accurate measurements. This paper demonstrates implementation of a Rayleigh scattering-type distributed temperature sensor in a thermal mixing experiment involving two air jets at 25 and 45 &#176;C. We present criteria to guide selection of optical fiber for the sensor and describe installation setup for a jet mixing experiment. We illustrate sensor baselining, which links readings to an absolute temperature standard, and discuss practical issues such as errors due to flow-induced vibration. This material can aid those interested in temperature measurements having high data density and bandwidth for fluid dynamics experiments and similar applications. We highlight pitfalls specific to these sensors for consideration in experiment design and operation.

We demonstrate use of a fiber optic distributed sensor for mapping the temperature field of mixing air jets. The Rayleigh scattering-based sensor generates thousands of data points along a single fiber to provide exceptional spatial resolution that is unattainable with traditional sensors such as thermocouples.

Temperaturfeldzuordnung Glasfaser verteilten Sensoren für hochauflösendes

The reliability of computational fluid dynamics (CFD) codes is checked by comparing simulations with experimental data. A typical data set consists ...

Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film.

A protocol for the synthesis of moisture-responsive luminescent Ag-zeolite composites is described in this report.

Nanostrukturierte Ag-Zeolith-Komposite als Lumineszenz-basierte Feuchtigkeitssensoren

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high ...

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape method or individual WS2 nanotubes by dispersing the suspension of WS2 nanotubes. The selected samples have been fabricated into devices by the use of the electron beam lithography and electrolyte is put on the devices. We have characterized the electronic properties of the devices under applying the gate voltage. In the small gate voltage region, ions in the electrolyte are accumulated on the surface of the samples which leads to the large electric potential drop and resultant electrostatic carrier doping at the interface. Ambipolar transfer curve has been observed in this electrostatic doping region. When the gate voltage is further increased, we met another drastic increase of source-drain current which implies that ions are intercalated into layers of WS2 and electrochemical carrier doping is realized. In such electrochemical doping region, superconductivity has been observed. The focused technique provides a powerful strategy for achieving the electric-filed-induced quantum phase transition.

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

Here, we present a protocol to control the carrier number in solids by using the electrolyte.

Elektrisches Feld Kontrolle der elektronischen Zustände in WS2 Nanosysteme durch Elektrolyt Anspritzung

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape ...

Ultrasonic Fatigue Testing in the Tension-Compression Mode

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on exposing the specimen to longitudinal vibrations on its resonance frequency close to 20 kHz. With use of this method, it is possible to significantly decrease the time required for the test, when compared to conventional testing devices usually working at frequencies under 200 Hz. It is also used to simulate loading of material during operation in high speed conditions, such as those experienced by components of jet engines or car turbo pumps. It is necessary to operate only in the high and ultra-high cycle region, due to the possibility of extremely high deformation rates, which can have a significant influence on the test results. Specimen shape and dimensions have to be carefully selected and calculated to fulfill the resonance condition of the ultrasonic system; thus, it is not possible to test the full components or specimens of arbitrary shape. Before each test, it is necessary to harmonize the specimen with the frequency of the ultrasonic system to compensate for deviations of the real shape from the ideal one. It is not possible to run a test until a total fracture of the specimen, since the test is automatically terminated after initiation and propagation of the crack to a certain length, when the stiffness of the system changes enough to shift the system out of the resonance frequency. This manuscript describes the process of evaluation of materials' fatigue properties at high-frequency ultrasonic fatigue loading with use of mechanical resonance at a frequency close to 20 kHz. The protocol includes a detailed description of all steps required for a correct test, including specimen design, stress calculation, harmonizing with the resonance frequency, performing the test, and final static fracture.

A protocol for ultrasonic fatigue testing in the high and ultra-high cycle region in axial tension-compression loading mode.

Ultraschall Ermüdungsprüfung im Zug-Druck-Modus

Ultrasonic fatigue testing is one of a few methods which allow investigating fatigue properties in the ultra-high cycle region. The method is based on ...

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 (STO) Single-crystal Substrates

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF) magnetron sputtering. LSMO nanoparticles were deposited with diameters from 10 to 20 nm and heights between 20 and 50 nm. At the same time, (Gd) Ba2Cu3O7&#8722;&#948; ((Gd) BCO) films were fabricated on both undecorated and LSMO nanoparticle decorated STO substrates using RF magnetron sputtering. This report also describes the properties of GdBa2Cu3O7&#8722;&#948;/ La0.67Sr0.33MnO3 quasi-bilayer films structures (e.g., crystalline phase, morphology, chemical composition); magnetization, magneto-transport, and superconducting transport properties were also evaluated.

Radio Frequency Magnetron Sputtering of GdBa2Cu3O7ÃƒÂ¢Ã‹â€ &#039;ÃƒÅ½ ´/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 STO Single-crystal Substrates

Here, we present a protocol to grow LSMO nanoparticles and (Gd) BCO films on (001) SrTiO3 (STO) single-crystal substrates by radio frequency (RF)-sputtering.

Radiofrequenz das Magnetron-Sputtern GdBa2Cu3O7−δ/ La0,67Sr0,33MnO3 quasi-Bilayer Filme auf SrTiO3 (STO) Einkristall Substraten

Here, we demonstrate a method of coating ferromagnetic La0.67Sr0.33MnO3 (LSMO) nanoparticles on (001) SrTiO3 (STO) single-crystal substrates by radio ...

Hybrid Printing for the Fabrication of Smart Sensors

A method to combine additively manufactured substrates or foils and multilayer inkjet printing for the fabrication of sensor devices is presented. First, three substrates (acrylate, ceramics, and copper) are prepared. To determine the resulting material properties of these substrates, profilometer, contact angle, scanning electron microscope (SEM), and focused ion beam (FIB) measurements are done. The achievable printing resolution and suitable drop volume for each substrate are, then, found through the drop size tests. Then, layers of insulating and conductive ink are inkjet printed alternately to fabricate the target sensor structures. After each printing step, the respective layers are individually treated by photonic curing. The parameters used for the curing of each layer are adapted depending on the printed ink, as well as on the surface properties of the respective substrate. To confirm the resulting conductivity and to determine the quality of the printed surface, four-point probe and profilometer measurements are done. Finally, a measurement set-up and results achieved by such an all-printed sensor system are shown to demonstrate the achievable quality.

Here we present a protocol for the fabrication of inkjet-printed multilayer sensor structures on additively manufactured substrates and foil.

Hybrid für die Herstellung von intelligenten Sensoren drucken

A method to combine additively manufactured substrates or foils and multilayer inkjet printing for the fabrication of sensor devices is presented. First, ...