Esta pesquisa é patrocinada pela Defense Advanced Research Projects Agency EUA nos Centros Integrados de Fotônica Pesquisa de Engenharia (cifra) programa com o Dr. J. Scott Rodgers como gerente de projeto. As informações fornecidas neste relatório não reflecte necessariamente a posição ou a política do Governo dos EUA e não endosso oficial deve ser inferida.

1. PDMS preparação de microsferas (Sphere I) <ol><li> Polidimetilsiloxano base (PDMS) e o agente de cura são misturados com uma relação de volume de 60:1. </li><li> Uma mecha de fibra óptica de sílica, cerca de 2 cm de comprimento, é primeiramente retirado do seu revestimento de plástico usando um separador óptico. </li><li> Uma extremidade da fibra é aquecida e esticada para proporcionar uma extremidade da haste, que é de aproximadamente 25-50 um de diâmetro na ponta. </li><li> A extremidade da fibra estirada é submerso na mistura PDMS por um comprimento de cerca de 2-4 mm e, em seguida, é puxada para fora. </li><li> Tensão superficial e peso da mistura PDMS permitir a formação de uma esfera na extremidade da fibra de silica. O tamanho da esfera é controlada pelo comprimento de imersão e velocidade de extracção. Ao variar estes dois parâmetros, diâmetros da esfera na gama de 100 um - 1.000 mM pode ser obtida. </li><li> A montagem de microsferas / haste é então colocada numa estufa a ~ 90 ° C durante 4 horas para permitir a consolidação adequada do polimer material (para formar ligações cruzadas cadeias). Figura 1a é um esquema de I. Sphere </li></ol> 2. PDMS baseado Preparação Esfera tripla camada (Sphere II) <ol><li> Uma microesfera 60:1 PDMS é utilizado como o núcleo interior. Os mesmos passos descritos em 1) acima é seguida por este processo. </li><li> Uma mistura de titanato de bário (BaTiO 3) nano-partículas e 60:1 PDMS é utilizado como a camada do meio. A mistura de PDMS, preparado da mesma maneira descrita no ponto 1.1), acima, é misturado com o titanato de bário nano-partículas. </li><li> O núcleo microesfera PDMS descrito em 2.1) é então mergulhado na mistura de titanato de bário PDMS-bata-(com uma espessura de camada nominal de ~ ^ M 10). </li><li> Em seguida, a esfera de duas camadas é colocado numa estufa a ~ 90 ° C durante 4 horas para permitir a cura apropriada da segunda camada. </li><li> Uma vez que a esfera de duas camadas é curado, é de novo imerso numa mistura de 60:1 de PDMS para proporcionar um revestimento exterior (terceira camada). Este externocamada serve como guia óptica esférica (~ 10 um de espessura). Figura 1b é um esquema de Sphere II. </li></ol> 3. Sílica / PDMS preparação de microsferas (Sphere III) <ol><li> A secção de ~ 3 cm de comprimento de uma fibra de modo único de sílica óptico é primeiramente retirado do seu tampão (em plástico) de revestimento e, em seguida, a sua ponta é fundida usando um micro-tocha (em conjunto com o revestimento e núcleo). Tensão superficial e gravidade trabalhar juntos para moldar a ponta derretido em uma esfera. Esferas com diâmetros variando de 200 a 500 um podem ser obtidas com este processo. </li><li> A microesfera de sílica é então imerso num banho de PDMS de base (sem o agente de cura) a cobri-lo com um revestimento de ~ 50 ^ m. Esta camada exterior permanece como um altamente viscoso Bingham líquido (limite elástico). Figura 1c é um esquema de Sphere III. </li></ol> 4. Preparação de fibra óptica <ol><li> Uma secção de uma fibra óptica de modo único é retirado da sua cla plásticodding utilizando um extractor óptico. Usando uma micro-tocha a secção listrado da fibra é aquecido até que seja fundido (tanto o revestimento e núcleo de fibra). </li><li> Embora a parte do meio é fundido, uma extremidade da fibra óptica é puxado ao longo do seu eixo de modo a formar uma secção cónica da fibra que é de cerca de 1 cm de comprimento. A duração do aquecimento, a velocidade de puxar e distância determinar o diâmetro da secção cónica que varia entre 10 e 20 um. A luz proveniente do laser DFB é acoplada para a esfera através da secção cónica da fibra. Figura 2 mostra o acoplamento de esfera de fibra. </li></ol> 5. Optoeletrônicos Setup <ol><li> A saída de um laser DFB sintonizável é acoplado a uma fibra óptica de modo único em uma extremidade e termina num fotodíodo rápido, na outra extremidade, como mostrado na Figura 3. </li><li> A saída do fotodíodo é digitalizada utilizando um conversor analógico-para-digital (A / D) e armazenados num computador pessoal (PC). </li><li&gt; Usando um estágio de translação-micro da microesfera (Tipo I, II ou III) é posto em contacto com a secção cónica da fibra óptica (Figuras 2 e 3) para proporcionar o acoplamento óptico entre estes dois elementos. </li><li> O laser DFB é ajustado por um controlador de laser. O controlador de laser, por sua vez, é accionado por um gerador de função que fornece uma tensão de entrada em dente de serra. </li></ol> 6. Geração de Campo Elétrico <ol><li> Duas placas de latão quadrados (2 x 2 cm) com a espessura de 1 mm, são utilizados para gerar o campo eléctrico uniforme. As placas são ligadas a uma fonte de tensão e os sensores de esfera são colocados no espaço entre as duas chapas (Figura 4). </li><li> A fim de aumentar a sensibilidade de medição, as esferas são primeiramente poled num campo eléctrico de 1 MV / m, durante 2 horas. </li></ol>

<ol>
	<li>von Klitzing, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tunable+whispering+gallery+modes+for+spectroscopy+and+CQED+experiments.">Tunable whispering gallery modes for spectroscopy and CQED experiments.</a> New journal of physics. 3, 14.1-14.14 (2001).</li><li>Cai, M., Painter, O., Vahala, K. J., Sercel, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fiber-coupled+microsphere+laser.">Fiber-coupled microsphere laser.</a> Optics letters. 25 (19), 1430-1432 (2000).</li><li>Tapalian, H. C., Laine, J. P., Lane, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermooptical+switches+using+coated+microsphere+resonators.">Thermooptical switches using coated microsphere resonators.</a> IEEE photonics technology letters. 14 (8), 1118-1120 (2002).</li><li>Little, B. E., Chu, S. T., Haus, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microring+resonator+channel+dropping+filters.">Microring resonator channel dropping filters.</a> Journal of lightwave technology. 15, 998-1000 (1997).</li><li>Offrein, B. J., Germann, R., Horst, F., Salemink, H. W. M., Beyerl, R., Bona, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resonant+coupler-based+tunable+add-after-drop+filter+in+silicon-oxynitride+technology+for+WDM+networks.">Resonant coupler-based tunable add-after-drop filter in silicon-oxynitride technology for WDM networks.</a> IEEE journal of selected topics in quantum electronics. 5, 1400-1406 (1999).</li><li>Ilchenko, V. S., Volikov, P. 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. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whispering-gallery+mode+evanescent-wave+microsensor+for+trace-gas+detection.">Whispering-gallery mode evanescent-wave microsensor for trace-gas detection.</a> Proceedings of SPIE. 4265, 102-112 (2001).</li><li>Ioppolo, T., Das, N., &#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=Whispering+gallery+modes+of+microspheres+in+the+presence+of+a+changing+surrounding+medium:+A+new+ray-tracing+analysis+and+sensor+experiment.">Whispering gallery modes of microspheres in the presence of a changing surrounding medium: A new ray-tracing analysis and sensor experiment.</a> Journal of applied physics. 107, 103105 (2010).</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=High-resolution+force+sensor+based+on+morphology+dependent+optical+resonances+of+polymeric+spheres.">High-resolution force sensor based on morphology dependent optical resonances of polymeric spheres.</a> Journal of applied physics. 105 (1), 013535 (2009).</li><li>Ioppolo, T., Kozhevnikov, M., Stepaniuk, V., &#214;t&#252;gen, M. V., Sheverev, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micro-optical+force+sensor+concept+based+on+whispering+gallery+mode+resonances.">Micro-optical force sensor concept based on whispering gallery mode resonances.</a> Applied optics. 47 (16), 3009-3014 (2008).</li><li>Ioppolo, T., &#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=Pressure+tuning+of+whispering+gallery+mode+resonators.">Pressure tuning of whispering gallery mode resonators.</a> Journal of optical society of America B. 24 (10), 2721-2726 (2007).</li><li>Ioppolo, T., &#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=Effect+of+acceleration+on+the+morphology+dependent+optical+resonances+of+spherical+resonators.">Effect of acceleration on the morphology dependent optical resonances of spherical resonators.</a> Journal of optical society of America B. 28, 225-227 (2011).</li><li>Ayaz, U. K., Ioppolo, T., &#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=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. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electric+field-induced+deformation+of+polydimethylsiloxane+polymers.">Electric field-induced deformation of polydimethylsiloxane polymers.</a> Journal of applied physics. 112, 044906 (2012).</li><li>Manzo, M., Ioppolo, T., Ayaz, U. K., LaPenna, V., &#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=A+photonic+wall+pressure+sensor+for+fluid+mechanics+applications.">A photonic wall pressure sensor for fluid mechanics applications.</a> Review of scientific instrumentation. 83, 105003 (2012).</li></ol>

Não temos nada a revelar.

As esferas são inicialmente polarizado através da ligação dos eléctrodos a uma fonte de tensão contínua elevada. No final da duração poling, os fios de eléctrodos foram desligados da fonte de tensão contínua e conectado a um gerador de função, tal como indicado na Figura 4. Os resultados apresentados nas Figuras 5 a 8 mostram que positivos e negativos campos eléctricos (em relação à direcção de poling) conduzem a esfera alongamento e de compressão, respectivamente. ...

<table border="1"><tbody><tr><td></td><td> Companhia </td><td> Número de catálogo </td><td> Comentários (opcional) </td></tr><tr><td> PDMS </td><td> Dow Corning </td><td> Sylgard 184 </td><td></td></tr><tr><td> Fibra de sílica </td><td> Instrumento de vendas de fibra </td><td> E-37AP15-FIS </td><td></td></tr><tr><td> Titanato de bário (BaTiO 3) nanopartículas </td><td> Sigma Aldrich </td><td> 467634-100G </td><td></td></tr><tr><td> Controlador Laser </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> Comprimento de onda central de 1,310 mM </td></tr><tr><td> Fotodiodo </td><td> Thorlabs </td><td> PDA10CS </td><td></td></tr><tr><td> A / D Cartão </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

Modos de óptica de micro-cavidades dielétricas têm recebido atenção significativa nos últimos anos devido ao seu potencial de uma ampla gama de aplicações. Os modos ópticos são freqüentemente referidos como &quot;sussurrando modos Galeria&quot; (WGM) ou &quot;ressonâncias morfologia dependentes&quot; (MDR) e apresentam altos fatores de qualidade óptica. Algumas aplicações propostas de micro-cavidade ressonadores ópticos são em espectroscopia 1, micro-cavidade tecnologia laser 2, 3-6 comunicações ópticas, bem como tecnologia de sensores. As aplicações baseadas WGM sensores incluem aqueles em biologia 7, traço de detecção de gás 8, e detecção de impurezas em líquidos 9. Sensores mecânicos com base em ressoadores de microsferas também têm sido propostos, incluindo os de força 10,11, a pressão 12, 13 e parede de aceleração tensão de corte 14. No presente, nós demonstramos uma WGM baseada em sensor de campo elétrico, que se baseia em nosso studi anteriores 15,16. A aplicação candidato deste sensor é na detecção de potencial de acção neuronal. O sensor de campo eléctrico é baseada em multi-camadas polimérico dieléctrico microesferas. O campo eléctrico externo induz superfície e as forças de corpo sobre as esferas (efeito electrostriction) que conduzem a uma deformação elástica. Esta mudança na morfologia das esferas, conduz a mudanças na WGM. Mudanças do campo elétrico induzidos WGM são interrogados por emocionantes os modos ópticos das esferas de luz laser. A luz de uma realimentação distribuída (DFB) laser (comprimento de onda nominal de ~ 1,3 mm) é o lado de acoplamento para as microesferas usando uma secção cónica de uma fibra óptica de modo único. O material de base das esferas é polidimetilsiloxano (PDMS). Três geometrias de microsferas são utilizados: (1) esfera PDMS com uma razão volumétrica de 60:1 de base-para-agente de cura mistura, (2) de camadas múltiplas com esfera 60:1 PDMS do núcleo, a fim de aumentar a constante dieléctrica do thesfera e, uma camada média de 60:1 PDMS que é misturado com quantidades variáveis ​​(2% a 10% por volume) de titanato de bário e uma camada exterior de 60:1 PDMS e (3) da esfera de sílica sólida revestida com uma fina camada da base de PDMS não curado. Em cada tipo de sensor, a luz do laser da fibra cónica é acoplada na camada mais externa que fornece alta qualidade óptica fator WGM (Q ~ 10 6). As microesferas são poled durante várias horas a campos eléctricos de ~ 1 MV / m para aumentar a sua sensibilidade ao campo eléctrico.

Um modo óptico (WGM) da esfera é excitado pela luz do laser quando comprimento do caminho óptico percorrido pela luz é um número inteiro múltiplo do comprimento de onda do laser. Pela disposição mostrada na Figura 3, o comprimento do caminho óptico é 2πrn, onde n e r são o índice de refracção e um raio da esfera, respectivamente. Usando aproximação óptica geométrica, uma condição WGM é satisfeita quando 2πrn = lλ onde I é um inteiro e...

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

Um sensor de alta sensibilidade fotónica micro foi desenvolvido para a detecção de campos eléctricos. O sensor explora os modos ópticos de uma esfera dielétrica. Mudanças no campo elétrico externo perturbar a morfologia esfera levando a mudanças em seus modos ópticos. A intensidade do campo eléctrico é medida por monitorização destas mudanças ópticas.

Desenvolvimento de Whispering Gallery Modo poliméricos Micro-ópticos sensores do campo eléctrico

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 visualizações.  Southern Methodist University. Um sensor de alta sensibilidade fotónica micro foi desenvolvido para a detecção de campos eléctricos. O sensor explora os modos ópticos de uma esfera dielétrica. Mudanças no campo elétrico externo perturbar a morfologia esfera levando a mudanças em seus modos ópticos. A intensidade do campo eléctrico é medida por monitorização destas mudanças ópticas.

Vídeo: 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.

Microwave Systems Fotônica Baseado Ressonadores-gallery de modo Whispering

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

Engenharia

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.

Real-Time DC-dinâmico método de polarização para a mudança de melhoria no tempo em Severamente subamortecido Fringing-campo eletrostático MEMS Atuadores

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.

Caracterização de anisotrópicos Leaky Modo moduladores para 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).

Estimulada Stokes e Antistokes Raman Scattering em microparticulas Whispering Gallery Modo Resonators

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.

Fibra Óptica sensores distribuídos para High-resolution Mapeamento Temperatura campo

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.

Composites nanoestruturado Ag-zeólita como sensores de umidade à base de luminescência

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.

Campo elétrico controle de Estados eletrônicos em WS2 nanodispositivos por retenção de eletrólitos

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.

Fadiga ultra-sônico de teste no modo de tensão-compressão

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.

Rádio frequência Magnetron Sputtering do GdBa2Cu3O7−δ/ La0,67Sr0,33MnO BICAMADA de quase3 filmes em substratos de único-cristal SrTiO3 (STO)

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.

Híbrido de impressão para a fabricação de sensores inteligentes

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