<p>The purpose of the diploma work is to investigate the possibilities to combine three different areas; reflectometry, microfluidics and laser ablation in a microstructured single-mode fiber, thus obtaining a controlled technique for positioning for ablation and collection of liquids from small inclusions.</p><p>Each of the three areas is thoroughly described in different sections of this report. The first part of the experiments in this diploma work consisted of combining reflectometry and microfluidics, the second part combining reflectometry with laser ablation and the final experiment setup consisted of a combination of all three areas. An artificial system for liquid collection was then designed for that purpose.</p><p>The results obtained from experiments and measurements clearly demonstrate that combining reflectometry, laser ablation and fluid collection in a single optical fiber is promising. Future work will include improvements of the technique towards a medical application for bone marrow transplantation.</p>

The purpose of the diploma work is to investigate the possibilities to combine three different areas; reflectometry, microfluidics and laser ablation in a microstructured single-mode fiber, thus obtaining a controlled technique for positioning for ablation and collection of liquids from small inclusions. Each of the three areas is thoroughly described in different sections of this report. The first part of the experiments in this diploma work consisted of combining reflectometry and microfluidics, the second part combining reflectometry with laser ablation and the final experiment setup consisted of a combination of all three areas. An artificial system for liquid collection was then designed for that purpose. The results obtained from experiments and measurements clearly demonstrate that combining reflectometry, laser ablation and fluid collection in a single optical fiber is promising. Future work will include improvements of the technique towards a medical application for bone marrow transplantation.

v Abstract This study was developed using fiber drawing tower to fabricate various types of capillary fiber and microstructured fiber. For example, different diameter sizes, different thickness, different internal diameter ratio of the capillary fiber and capillary tube, single ring and double ring hexagonal arrangement of the air-holes microstructured fiber. Trying different ways to create complex structures preform, we use the stack - drawing - cutting way, is now able to produce only simple pressure can be achieved by the complex structure of the preform, compared to drilling way, we can effectively reduce the production costs of 80%. Now successfully produced a single ring and double ring hexagonal air holes arranged in preform which has been drawn into standard fiber. Depending on the optical properties, we can use quartz tube with a row of self-developed method to produce most of the complex structure of the preform. However, each fiber is still not very uniform about the pores, which we need to improve in the manufacturing process of fiber drawing. Produce more diverse system and much homogeneous microstructured fiber as the goal. Application is to use the self-fabricated capillary tube, after processing, the production target into a low-loss device, then inject different materials within the devices, and do the different optical measurements for our devices.

The magnetization damping properties of square permalloy elements were characterized. These 20 nm-thick permalloy squares were deposited by the electron beam evaporation. Time resolved magneto-optic Kerr effect microscopy (TR-MOKE) was used to measure the magnetization evolution in the sample. By curve fitting in Matlab, I obtained the value of damping constant that is consistent with the reference paper. A Landau confi guration in the square permalloy sample leads to the different trends of the damping constant with external bias field. The damping constant in the bottom domain is found to decrease with increasing bias field while the damping constant in the top domain has been saturated into the minimum value. The decreasing tendency of magnetization precession frequencies is consistent with the Kittel equation modi fied with an anisotropic energy term. Additionally, FePt thin films and patterned CoFeB disks were investigated but neither yielded conclusive dynamic data. / Graduate / 0611 / 0607 / 0752 / leizhang.summer@gmail.com

Orientador: Cristiano Monteiro de Barros Cordeiro / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-09-02T14:50:23Z (GMT). No. of bitstreams: 1 Osorio_JonasHenrique_D.pdf: 57449332 bytes, checksum: 92f06bf0e96b31630478243a818a7fd6 (MD5) Previous issue date: 2017 / Resumo: Nesta tese, fibras ópticas especiais são estudadas para fins de sensoriamento. Primei-ramente, propomos a estrutura denominada fibra capilar com núcleo embutido (embedded-core capillary fibers) para realização de sensoriamento de pressão. Estudos numéricos e analíticos foram realizados e mostraram que altas sensibilidades a variações de pressão poderiam ser al-cançadas com esta estrutura simplificada, que consiste de um capilar dotado de um núcleo, dopado com germânio, em sua parede. Experimentos permitiram medir uma sensibilidade de (1.04 ± 0.01) nm/bar, que é um valor alto quando comparado a outros sensores de pressão ba-seados em fibras microestruturadas. Ademais, estudamos fibras do tipo surface-core, que são fibras cujos núcleos são colocados na superfície externa da fibra. Nesta abordagem, redes de Bragg foram utilizadas para obter sensores de índice de refração ¿ fazendo-se uso da interação entre o campo evanescente do modo guiado no núcleo e o ambiente externo à fibra ¿ e de cur-vatura ¿ ao se explorar o fato de que, nestas fibras, o núcleo se encontra fora do centro geomé-trico da mesma. As sensibilidades a variações de índice de refração e curvatura medidas, 40 nm/RIU em torno de 1.41 e 202 pm/m-1 comparam-se bem a outros sensores baseados em redes de Bragg. Outrossim, fibras capilares poliméricas foram investigadas como sensores de temperatura e pressão. Para a descrição do sensor de temperatura, usou-se um modelo analítico para simular o espectro de transmissão dos capilares e a sua dependência com as variações de temperatura. No que tange à aplicação de sensoriamento de pressão, variações nas espessuras dos capilares devido à ação da pressão foram calculadas e relacionadas à sensibilidade da me-dida de monitoramento. Nestas duas aplicações, realizações experimentais também são repor-tadas. Finalmente, oportunidades adicionais de sensoriamento ao se utilizar fibras ópticas es-peciais são apresentadas, a saber, um sensor de pressão para dois ambientes baseados em fibras de cristal fotônico, um sensor de três parâmetros baseado em redes de Bragg, fibras afinadas e interferência multimodal, um sensor de nível de líquido baseado em redes de Bragg e interfe-rência multimodal e um sensor de temperatura baseado em fibras embedded-core preenchidas com índio. Os resultados aqui reportados demonstram o potencial das fibras ópticas em forne-cerem plataformas de sensoriamento para alcançar medidas de diferentes tipos de parâmetros com alta sensibilidade e resolução adequada / Abstract: In this thesis, specialty optical fibers for sensing applications are investigating. Firstly, we propose the embedded-core capillary fiber structure for acting as a pressure sensor. Analyt-ical and numerical studies were performed and showed that high pressure sensitivity could be achieved with this simplified fiber structure, which consists of a capillary structure with a germanium-doped core placed within the capillary wall. Experiments allowed measuring a sensitivity of (1.04 ± 0.01) nm/bar, which is high when compared to other microstructured optical fiber-based pressure sensors. Moreover, we studied the so-called surface-core optical fibers, which are fibers whose cores are placed at the external boundary of the fiber. In this approach, Bragg gratings were used to obtain refractive index ¿ making use of the interaction between the guided mode evanescent field and the external medium ¿ and directional curva-ture sensors ¿ by exploring the off-center core position. The measured refractive index and the curvature sensitivities, respectively 40 nm/RIU around 1.41 and 202 pm/m-1, compares well to other fiber Bragg grating-based sensors. Additionally, antiresonant polymer capillary fibers were investigated as temperature and pressure sensors. For the temperature sensing descrip-tion, one used an analytical model to simulate the transmission spectra of such fibers and the dependence on temperature variations. Regarding the pressure sensing application, pressure-induced capillary wall thickness variations were analytically accounted and related to the sys-tem pressure sensitivity. In both these applications, experimental data were presented. Finally, additional opportunities using specialty optical fibers were presented, namely, a photonic-crystal fiber-based dual-environment pressure sensor, a three parameters sensor using Bragg gratings, tapered fibers and multimode interference, a liquid-level sensor based on Bragg grat-ings and multimode interference, and a temperature sensor based in an embedded-core fiber filled with indium. The results reported herein demonstrates the potential of optical fibers for providing sensing platforms to attain measurements of different sort of parameters with highly sensitivity and improved resolutions / Doutorado / Física / Doutor em Ciências / 152993/2013-4 / CNPQ

This paper describes a promising fabrication technique for rapid replication of high aspect ratio microstructured molds for UV embossing. The process involves casting silicone rubber on a microstructured master, replicating an epoxy mold using the PDMS rubber mold and finally, metallizing the surfaces of the epoxy mold by electroless plating nickel (EN). The preliminary study suggests that this technique is feasible for rapid replication of high aspect ratio molds for UV embossing. Uniform molds can be replicated rapidly through this technique making the process economical and accessible. / Singapore-MIT Alliance (SMA)

Η παρούσα εργασία εστιάζει στη μελέτη αισθητήρων με χρήση μικροδομημένων οπτικών ινών (ή οπτικών ίνών φωτονικών κρυστάλλων) με δύο πυρήνες, οι οποίοι αλληλεπιδρούν μεταξύ τους. Για την πληρότητα της μελέτης γίνεται αρχικά μια ανασκόπηση των βασικών χαρακτηριστικών των ινών φωτονικών κρυστάλλων όπως οι απώλειες, η διασπορά, και το φαινόμενο της περιοδικής μεταφοράς ενέργειας μεταξύ των πυρήνων σε μία διπύρηνη ίνα φωτονικών κρυστάλλων. Το τελευταίο αποτελεί βάση για τη λειτουργία της ίνας ως αισθητήρα. Στη συνέχεια, αναλύονται τα βασικά χαρακτηριστικά των αισθητήρων μικροδομημένων οπτικών ινών και μελετάται η ευαισθησία συναρτήσει του μήκος κύματος της διαδιδόμενης ακτινοβολίας και των γεωμετρικών χαρακτηριστικών της ίνας. Πιο συγκεκριμένα, μελετάται η ευαισθησία για τρία μοντέλα ινών, με μία, δύο και τρεις οπές μεταξύ των πυρήνων τους. Ως υλικό γεμίσματος των οπών θεωρήθηκε το νερό, διότι είναι ένας από τους πιο κοινούς διαλύτες, κατάλληλος και για βιολογικά δείγματα. Για κάθε ένα από τα παραπάνω μοντέλα εξετάζεται η συμπεριφορά του αισθητήρα συναρτήσει του μήκους κύματος της διαδιδόμενης ακτινοβολίας. Ακολούθως, μελετάται η συμπεριφορά των αισθητήρων όταν υποβληθούν σε μεταβολή κλίμακας (scaling), δηλαδή όταν μεταβληθούν ταυτόχρονα όλες οι γεωμετρικές παράμετροι του αισθητήρα, κρατώντας σταθερές τις αναλογίες. Ο λόγος για τον οποίο γίνεται αυτό είναι διότι αυξάνοντας την διατομή της ίνας αυξάνει παράλληλα η διάμετρος των οπών με αποτέλεσμα να διευκολύνεται το γέμισμά τους με το υπό μελέτη υλικό. Όμως, καθώς αυξάνεται η διατομή της ίνας αυξάνει παράλληλα και η απόσταση μεταξύ των πυρήνων, μειώνοντας έως εξαλείφοντας την αλληλεπίδρασή τους. Για το λόγο αυτό παρουσιάζεται μια βελτιωμένη μορφή του αισθητήρα με κεντρικές οπές στους δύο πυρήνες, με σκοπό το άπλωμα των ρυθμών και κατά συνέπεια την αύξηση της αλληλεπίδρασης μεταξύ των πυρήνων. Κατ’ αυτόν τον τρόπο η μικροδομημένη ίνα μπορεί να λειτουργήσει ως αισθητήρας για σχετικά μεγάλες τιμές της μεγέθυνσης, κάτι που δεν είναι δυνατόν απουσία κεντρικών οπών. Τέλος, παρουσιάζονται αποτελέσματα και για ένα μοντέλο αισθητήρα συμβατικής οπτικής ίνας με δύο πυρήνες και κεντρικές οπές, το οποίο στηρίζεται στην ίδια αρχή λειτουργίας και παρουσιάζει παρόμοια συμπεριφορά με τις διπύρηνες μικροδομημένες ίνες. / This MSc thesis focuses on the study of sensors using microstructured optical fibers (or photonic crystal optical fibers) with two cores, which interact with each other. For the completeness of the study, first is attempted an overview of the basic characteristics of the photonic crystal fiber such as losses, dispersion and the effect of periodic transfer of energy among the cores in a dual core photonic crystal fiber. The latter forms the base for the operation of the fiber as sensing element. Then, the basic characteristics of the sensors using microstructured optical fibers are examined and the sensitivity is studied depending on the wavelength of the propagating radiation and on the geometric characteristics of the fiber. Specifically, the sensitivity of the sensor is studied for three fiber models with one, two and three holes between their cores. Water is assumed as filling material of the holes, since it is one of the most common dissolvers, also suitable for biological samples. For each model the behaviour of the sensor depending on the wavelength of the propagating radiation is studied. Afterwards, the behaviour of the sensor under scaling of the fiber dimensions is studied. In more detail all the geometrical parameters of the sensor are changed simultaneously and proportionally. From a practical point of view increasing the fiber dimensions facilitates the filling of the holes with the material under study. However, the distance between the cores is also increased, reducing or even eliminating their interaction. Therefore, an improved form of the sensor is presented. This form has central holes in the cores in order to extend the spatial overlap of the modes increasing the interaction between the cores. This way, the microstructured fiber can operate as a sensor even for relatively large scaling, which is not possible without central holes. Finally, a conventional model of ordinary dual core optical fiber sensor is studied, having central holes in both cores. It is based on the same principle of operation and has similar behaviour with the dual core microstructured optical fibers.

With the rise of capillary HPLC systems, open tubular liquid chromatography (OTLC) has been garnering more attention due to the possible fundamental advantages of open tubular systems over conventional packed or monolithic systems. Performance has yet to reach its potential due in part to a variety of technical challenges, resulting in the need for very small injection volumes and sensitive detection. In this work, we have shown that with modern HPLC sample introduction and detection systems, along with careful fabrication of polymer stationary phases, that reverse phase open tubular liquid chromatography may be within reach. We have shown that, with small diameter (i.d. 30m) open tubular columns, complex multi-component mixtures (EPA 610, in-house drug mixture) can be separated. We have also shown that these columns are robust and can function over a wide range of flow rates (200-1000 nl/min), and may be useful for general reverse phase separation in the future. However, currently, more stationary phase development and procedure refinement is needed. Microstructured fibres (MSFs), a relatively new class of optical fibre which confine light within fibres through a refractive index change caused by the use of parallel air channels running throughout the length of the fibre, are explored as a new support material for open tubular liquid chromatography. The fine channel structures of MSFs enable reasonable sample volumes to be used compared to conventional open tubular systems, while offering a similar plug-like flow profile through the fibre. With current sample introduction and flow technologies, we have shown that the potential advantages of MSF columns is great even when simple C18 stationary phases are used; this was able to separate a four PAH mixture. However, a distribution in channel sizes caused by current manufacturing standards and a limited ability to evenly deposit polymer stationary phases in the fibres has kept MSF columns from reaching their full potential. / Thesis (Master, Chemistry) -- Queen's University, 2011-09-14 11:52:41.23

Les verres de chalcogénures combinent plusieurs propriétés : une transparence étendue dans l’infrarouge, un indice de réfraction élevé (n>2) et de fortes propriétés non-linéaires. La réalisation de fibres optiques microstructurées (FOMs) permet d’exacerber les effets non-linéaires et notamment en faisant varier les paramètres optogéométriques des fibres (d et Λ). Ainsi, des fibres à propagation monomode peuvent être obtenues ou encore des fibres dont les applications potentielles concernent l’optique active avec la génération d’effets non-linéaires. La réalisation de telles fibres passent par la synthèse de verres de chalcogénures de haute pureté. Par conséquent, les bandes d’absorption limitant la transparence des fibres doivent être identifiées et limitées au maximum. Pour cela, le suivi et la qualification des éléments utilisés lors de la synthèse des verres doivent être entrepris. Un protocole de synthèse et de purification par traitements thermiques a été mis en place en ce sens. La technique pour élaborer les FOMs en verres de chalcogénures est le moulage. Elle consiste à couler un verre dans un moule entièrement réalisé en silice. Ce dernier présente la géométrie inverse de la fibre désirée. Cette méthode permet d’obtenir des géométries variées et reproductibles en passant par des fibres monomodes et multimodes avec des diamètres de cœur allant de 2 μm jusqu’à plus de 20 μm. La réalisation de sources infrarouges a été développée dans le manuscrit. Cela a été rendu possible dans un premier temps par la génération d’un supercontinuum à l’aide d’une fibre à cœur suspendu puis par la réalisation d’un laser à cascade quantique (QCL) couplé à une fibre monomode. De plus, une fibre à maintien de la polarisation (FMP) dans le moyen infrarouge, présentant une biréfringence de groupe de l’ordre de 10-3 a été élaborée grâce à l’évolution du moule de silice. De plus, un coupleur tout-optique, une fibre toute-solide et un faisceau de fibres infrarouges complètent les réalisations obtenues au cours de cette thèse. / Chalcogenide glasses combine several properties : large transparency in the infrared range, a high refractive index (n>2) and strong non-linear properties. The realization of microstructured optical fibers (MOFs) exacerbates non-linear effects more particularly by varying the opto-geometrical parameters of the fibers (d and Λ). Thus, single-mode propagation can be obtained and also generation of non-linear effects. The realization of high purity chalcogenide glasses is needed. In fact, absorption bands limiting the transparency of the fibers must be identified and minimized. For this, monitoring and qualification of components used in the synthesis of glasses should be undertaken. A protocol of synthesis and purification by heat treatment was implemented in this direction. The technique to elaborate MOFs is the casting method. It consists of flowing a glass on a silica mold. The geometry is the negative shape of the desired fiber. This method allows the realization of multimode or single-mode fiber in the 1-10 μm window. The realization of infrared sources was developed in the manuscript. The generation of a supercontinuum with a suspended-core fiber has been presented and also by the realization of a quantum cascade laser (QCL) coupled into a singlemode fiber. In addition, a polarization-maintaining fiber (PMF) having a group birefringence of the order of 10-3 was developed through the evolution of the silica mold. In addition, an optical coupler, an all-solid fiber and an infrared bundle were achieved during this thesis.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Douglas S. McGregor / The microstructured semiconductor neutron detector (MSND) was investigated and previous designs were improved and optimized. In the present work, fabrication techniques have been refined and improved to produce three-dimensional microstructured semiconductor neutron detectors with reduced leakage current, reduced capacitance, highly anisotropic deep etched trenches, and increased signal-to-noise ratios. As a result of these improvements, new MSND detection systems function with better gamma-ray discrimination and are easier to fabricate than previous designs. In addition to the microstructured diode fabrication improvement, a superior batch processing backfill-method for 6LiF neutron reactive material, resulting in a nearly-solid backfill, was developed. This method incorporates a LiF nano-sizing process and a centrifugal batch process for backfilling the nanoparticle LiF material. To better transition the MSND detector to commercialization, the fabrication process was studied and enhanced to better facilitate low cost and batch process MSND production. The research and development of the MSND technology described in this work includes fabrication of variant microstructured diode designs, which have been simulated through MSND physics models to predict performance and neutron detection efficiency, and testing the operational performance of these designs in regards to neutron detection efficiency, gamma-ray rejection, and silicon fabrication methodology. The highest thermal-neutron detection efficiency reported to date for a solid-state semiconductor detector is presented in this work. MSNDs show excellent neutron to gamma-ray (n/γ) rejection ratios, which are on the order of 106, without significant loss in thermal-neutron detection efficiency. Individually, the MSND is intrinsically highly sensitive to thermal neutrons, but not extrinsically sensitive because of their small size. To improve upon this, individual MSNDs were tiled together into a 6x6-element array on a single silicon chip. Individual elements of the array were tested for thermal-neutron detection efficiency and for the n/γ reject ratio. Overall, because of the inadequacies and costs of other neutron detection systems, the MSND is the premier technology for many neutron detection applications.