Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: Multiphoton fluorescence excitation microscopy (MPM) is an invaluable tool for studying processes in tissue in live animals by enabling biologists to view tissues up to hundreds of microns in depth. Unfortunately, imaging depth in MPM is limited to less than a millimeter in tissue due to spherical aberration, light scattering, and light absorption. Spherical aberration is caused by refractive index mismatch between the objective immersion medium and sample. Refractive index heterogeneities within the sample cause light scattering. We investigate the effects of refractive index mismatch on imaging depth in MPM. Methods: The effects of spherical aberration on signal attenuation and resolution degradation with depth are characterized with minimal light absorption and scattering using sub-resolution microspheres mounted in test sample of agarose with varied refractive index. The effects of light scattering on signal attenuation and resolution degradation with depth are characterized using sub-resolution microspheres in kidney tissue samples mounted in optical clearing media to alter the refractive index heterogeneities within the tissue. Results: The studies demonstrate that signal levels and axial resolution both rapidly decline with depth into refractive index mismatched samples. Interestingly, studies of optical clearing with a water immersion objective show that reducing scattering increases reach even when it increases refractive index mismatch degrading axial resolution. Scattering, in the absence of spherical aberration, does not degrade axial resolution. The largest improvements in imaging depth are obtained when both scattering and refractive index mismatch are reduced. Conclusions: Spherical aberration, caused by refractive index mismatch between the immersion media and sample, and scattering, caused by refractive index heterogeneity within the sample, both cause signal to rapidly attenuate with depth in MPM. Scattering, however, seems to be the predominant cause of signal attenuation with depth in kidney tissue. Kenneth W. Dunn, Ph.D., Chair

The use of receptor-targeted lipid microbubbles imaged by ultrasound is an innovative method of detecting and localizing disease. However, since ultrasound requires a medium between the transducer and the object being imaged, it is impractical to apply to an exposed surface in a surgical setting where sterile fields need be maintained. Additionally, the application of an ultrasound gel to the imaging surface may cause the bubbles to collapse. Multiphoton microscopy (MPM) is an emerging tool for accurate imaging of tissues and cells with high resolution and contrast. We have recently developed a novel method for detecting targeted microbubble adherence to the upregulated plectin-receptor on pancreatic tumor cells using MPM. Specifically, the third-harmonic generation response can be used to detect bound microbubbles to various cell types presenting MPM as an alternative and useful imaging method. This is an interesting technique that can potentially be translated as a diagnostic tool for the early detection of cancer and inflammatory disorders.

Cell cultures provide researchers the opportunity to observe cell behavior in response to specific, well-defined environmental cues, leading to insights that enable better engineering design for tissue culture and other biomedical applications. Chemical and electrical stimuli have been successfully applied to cultured cells to approximate aspects of the dynamic conditions experienced in vivo. However, in vitro topographical cues have mostly been limited to static substrates that do not subject cells to the dynamic conditions they experience in vivo when tissue remodels during development and wound healing. Delivering dynamic topographical cues to cultured cells can answer long-standing questions about mechanisms of cell morphology changes. Such capabilities could also facilitate engineering of wound-healing matrices and nerve guidance conduits by promoting migration of cells and providing directional guidance to cellular processes. This dissertation describes the development of approaches for introducing in situ topographical cues to cell cultures and inducing responses such as neurite guidance and cell alignment. Both strategies undertaken in this work make use of multiphoton-promoted photochemistry to print and manipulate three-dimensional microscopic protein hydrogel structures. In one approach, a technique referred to as micro-3D printing, topographical guidance cues are printed in the proximity of cultured cells to guide the growth of cellular processes. By translating a tightly-focused pulsed laser beam through a printing reagent solution flooding cultured cells, features are printed that provide physical guidance to extending neurites from NG108-15 cells, a neuronal model cell type. In another approach, an innovative technique known as micro-3D imprinting is developed for producing micrometer-scale depressions on the surfaces of photoresponsive protein hydrogels. The impact of various experimental parameters on topographical feature dimensions is characterized. Micro-3D imprinting is used to introduce dynamic topographical changes on a cell culture substrate, demonstrating that NIH-3T3 cells, a fibroblast cell model, alter their morphology and alignment in response to the introduction of a grooved surface topography. This set of approaches introduces new tools to the repertoire of cell biologists for exploring the behavior of cells growing in a spatio-temporally dynamic environment, opening possibilities for studies of cellular behavior in conditions that may better reflect environments cells experience in vivo. / text

Optical manipulation covers a wide range of techniques to guide and trap cells using only the forces exerted by light. Another optical tool is photoporation, the technique of injecting membrane-impermeable molecules using light, which has become an important alternative to other injection techniques. Together they provided sterile tools for manipulation and molecule delivery at the single-cell level. In this thesis, the properties of low Reynolds fluid flows are exploited to guide cells though a femtosecond Bessel beam. This design allows for high-throughput optical injection of cells without the need to individually target cells. A method of 'off-chip' hydrodynamic focusing was evaluated and was found to confine 95.6% of the sample within a region which would receive a femtosecond dose compared to 20% without any hydrodynamic focusing. The system was tested using two cell lines to optically inject the membrane-impermeable dye, propidium iodide. This resulted in an increase of throughput by an order of magnitude compared to the previous microfluidic design (to up to 10 cells per second). Next optical trapping and photoporation were combined to create a multimodal workstation. The system provides 3D beam control using spatial light modulators integrated into a custom user interface. The efficiency of optical injection of adherent cells and trapping capabilities were tested. The development of the system provides the groundwork for exploration of the parameters required for photoporation of non-adherent cells. Finally optical trapping is combined with temporally focused multiphoton illumination for scanless imaging. The axial resolution of the system was measured using different microscope objectives before imaging cells stained with calcein. Both single and a pair of recently trypsinised cells were optically trapped and imaged. The position of the trapped cells was manipulated using a spatial light modulator in order to obtain a z-stack of images without adjusting the objective position.

Semiconductors provide an interesting platform for studying light-matter interactions due to their unique electrically conductive behavior which can be deliberately altered in useful ways with the controlled introduction of confinement and doping, which changes the electronic band structure. This area of research has led to many important fundamental scientific discoveries that have in turn spawned a plethora of applications in areas such as photonics, microscopy, single-photon sources, and metamaterials. Silicon is the prevalent semiconductor platform for microelectronics because of its cost and electrical properties, while III-V materials are optimal for optoelectronics because of the ability to engineer a direct bandgap and create versatile heterojunctions by growing binary, ternary, or quaternary compounds.

O desenvolvimento da fotônica integrada vem recebendo muita atenção nos últimos anos. Sua alta funcionalidade e velocidade de transmissão de sinais possibilitam a aplicação em diversas áreas, que vão desde comunicações até biologia. O uso de polímeros em circuitos fotônicos integrados tem se mostrado interessante, pois compostos orgânicos podem ser facilmente incorporados a matrizes poliméricas. Isso faz com que as propriedades físicas do polímero possam ser modificadas de acordo com os materiais incorporados. Além disso, a técnica da fotopolimerização por absorção de dois fótons torna possível a produção de microestruturas poliméricas tridimensionais com alta resolução. A incorporação dessas microestruturas a circuitos fotônicos pode trazer um novo ramo de funcionalidades devido à facilidade de modificação das propriedades dos polímeros. Além disso, a tridimensionalidade das estruturas permite a realização de conexões ópticas em três dimensões, o que colabora para o aumento da compacticidade dos dispositivos fotônicos. No entanto, para que estas microestruturas possam ser efetivamente incorporadas aos circuitos fotônicos é necessário desenvolver formas de conectá-las a fontes externas de excitação, bem como a instrumentos de análise de sinais. Os tapers de fibras ópticas, também conhecidos como microfibras ou nanofibras, são bons candidatos para realizar essa tarefa devido a suas dimensões reduzidas, as quais são compatíveis com o tamanho das microestruturas. Neste trabalho desenvolvemos métodos para realizar a conexão óptica entre microestruturas poliméricas e tapers de fibras ópticas. As microestruturas foram produzidas através da técnica de fotopolimerização por absorção de dois fótons e corantes orgânicos foram incorporados à matriz polimérica para conferir propriedades fluorescentes às estruturas. Os tapers foram produzidos a partir de fibras ópticas convencionais por uma técnica de aquecimento e estiramento. Para realizar a conexão óptica, dois métodos foram desenvolvidos. No primeiro deles as microestruturas foram excitadas através de uma lente objetiva e sua emisão foi coletada por um taper. No segundo método, tanto a excitação quanto a coleta foram realizadas por tapers de fibras ópticas. Em ambos os casos as fibras foram posicionadas através de micromanipuladores. Os resultados obtidos indicam que os tapers são ferramentas adequadas para realizar tanto a excitação quando a coleta da emissão de microestruturas, pois permitem excitação individual e coleta localizada. Produzimos microestruturas com múltiplas dopagens e pudemos concluir que a excitação localizada de diferentes partes da estrutura, bem como a correta escolha do comprimento de onda de excitação, são mecanismos que levam a alterações no espectro de emissão, o que torna estas estruturas candidatas a fontes de luz sintonizáveis que podem ser incorporadas a dispositivos on-chip. Por fim, desenvolvemos um método de produção de microestruturas conectadas a tapers. Este trabalho abre caminho para a incorporação de microestruturas poliméricas a circuitos fotônicos e demonstra que tapers de fibras ópticas são ferramentas eficientes para a realização de microconexões ópticas. / The development of integrated photonics has received a great deal of attention in the last few years. Its high functionality and signal transmission speed allow applications in several fields, from telecommunications to biology. The use of polymeric platforms in integrated photonic circuits is interesting because organic compounds can be easily incorporated to polymeric matrixes, which makes it easy to change the physical properties of the polymer according to the embed materials. Furthermore, the two-photon polymerization technique allows the production of three-dimensional polymeric microstructures with high resolution. The incorporation of these microstructures to photonic circuits paves the way for a new field of funcionalities due to the ease of modification of the polymers properties. Besides that, the structures three-dimensionality allows the performance of optical connections in three dimensions, which can improve the compacticity of the photonic devices. However, for the effective incorporation of these microstructures to photonic circuits, it is necessary to develop ways to connect them to external excitation sources, as well as analysis instruments. Optical fiber tapers, also known as microfibers or nanofibers, are good candidates for this task due to their reduced dimensions that are compatible with the size of the microstructures. In this work we developed methods for the performance of optical connections of polymeric microstructures through fiber tapers. The microstrutures were produced through the two-photon polymerization technique and organic dyes were incorporated to the polymeric matrix in order to introduce fluorescent properties. The fiber tapers were produced from conventional optical fibers through a heat-and-draw approach. To perform the optical connections, two methods were developed. In the first one, the microestructures were excited through a microscope objective and emission collection was performed by a fiber taper. In the second approach, excitation and collection were performed by fiber tapers. In both methods, the tapers were set up by micromanipulators. The obtained results indicate that tapers are a suitable tool to perform optical excitation and emission collection in microstructures, as they allow individual excitation and localized collection. Multiple doped microstructures were produced and we could imply that the localized excitation of different parts of the structures, as well as the correct choice of the excitation wavelength, are tools that lead to changes in the emission spectrum, which makes these structures candidates to tunable light sources that can be incorporated to on-chip devices. At last, we developed a method for the production of microstructures connected to fiber tapers. This work paves the way for the incorporation of polymeric microstructures to photonics circuits and demonstrates that fiber tapers are efficient tools to perform optical microconnections.

Esta tese explora a potencialidade da radiação roveniente de um laser de gás carbônico para iniciar a combustão-modelo de substâncias simples oxigenadas com o bjetivo de estabelecer algumas das reações elementares relevantes ao processo de combustão. Esta tese é baseada no fato de que espécies intermediárias são geradas frequentemente em estados eletrônicos excitados no pulso do laser. O decaimento destas espécies em função do tempo foi observado pelas medidas de emissão por meio de uma fotomultiplicadora acoplada a filtros de interferência de banda estreita e, registrado em um osciloscópio de 100 MHz cuja base de tempo é gatilhada pelo laser de CO2. A evolução temporal do sinal de emissão foi analisada por um modelo cinético que compreende: 1) um processo de de pseudo-primeira ordem resultante por excitação multifotônica vibracional de colisões moduladas, e 2) decaimento através de emissão espontânea, reações químicas ou supressão radiativa. A cinética resultante das curvas experimentais foi obtida por um método de ajuste de curvas por simulação em um microcomputador. Os sistemas químicos estudados nesta tese compreendem o metanol, etanol, n-propanol, n-butanol e o éter dietílico. A eficiência na formação de C2, CH e OH foi estabelecida pela medida da intensidade e o tempo de subida da quimiluminescência determinado de acordo com o procedimento mencionado acima. A análise das curvas de subida e descida foram estudadas com o precursor puro e na presença de Ar, O2, NO, H2, Cl2, CH4 e C2H6, utilizando nestes casos pressões relativamente altas para garantir um número elevado de colisões. Nos sistemas em mistura com ar ou O2 as espécies emissivas CH e OH apresentam um prolongamento do tempo de decaimento, em geral não-exponencial. Ao mesmo tempo a intensidade relativa dos sinais de quimiluminescência atinge um máximo, sendo particularmente significativa para a espécie OH a uma determinada pressão de oxigênio. Misturas de etanol com O2/Ar resultam para a espécie OH num aumento no valor da vida média radiativa, enquanto que em misturas com CO, C2H6 e propileno (C3H6) é observado uma diminuição significativa. No caso de CO este comportamento é assumido como sendo de processos de relaxação, tendo-se para os dois últimos um processo de abstração de hidrogênio por parte da espécie OH. A presença de um inibidor de reações de radicais livres, NO, tem pouco efeito nos valores das constantes das espécies estudadas. Entretanto, a emissão da espécie OH foi totalmente suprimida em misturas do precursor com Cl2. Neste caso a observação de CH3CL por cromatografia em fase gasosa sugere que reações químicas de alguns dos fragmentos primários inibem o adicional bombeamento pelo laser. Um modo particular de se interpretar o possivel mecanismo de formação das espécies transientes, foi desenvolvido através do cálculo teórico RRKM dos principais processos primários aventados para a decomposição por excitação multifotônica vibracional da molécula de etanol. O cálculo RRKM foi modelado para a eliminação de H2O, processo majoritário a pressões baixas, e diferentes processos de cisões que passam a ter importância a intensidades elevadas de laser. O cálculo teórico mostra claramente que a eliminação de H2O é o canal preferido a baixas energias de excitação, sendo rapidamente reposto pelos outros canais a valores maiores de energia. Um efeito similar é observado para a decomposição unimolecular completa em função da pressão, onde a pressões elevadas, os processos de cisão com produção de radicais livres são dominantes como conseqüência da desativação das moléculas com energia mínima antes que sofram reação química. / This thesis explores the use of a CO2 laser to initiate combustion type reactions in a number of simple oxygen containing organic compounds. This method offers a potential tool to isolate and establish some of the elementary reactions responsible for the initial steps of combustion reactions. The core of the thesis is based on the fact that transient chemical species are generated in electronically excited states by the laser pulse. The time dependent behavior of this species has been observed by measuring the emission on a fast photomultiplier provided with narrow band filtres, and recording it on a 100 MHz oscilloscope triggered by the laser pulse. The time evolution of the emission signal has been analyzed by a kinetic model which includes: 1) an ill-defined pseudo-first arder process as a consequence of collisionally modulated multiphoton vibrational excitation, and 2) decay through spontaneous emission, chemical reaction ar radiative quenching. The resulting kinetics were fitted to the experimental curves by computer simulation. The chemical systems covered in this thesis include methanol, ethanol, n-propanol, n-butanol and diethyl ether. Under pulsed CO2 laser radiation, the efficiency of formation of C2, CH and OH have been established by intensity measurements and the rise time for chemiluminescence determined according to the procedure mentioned above. Emission rise times and decays were studied for the neat systems and in the presence of Ar, O2, NO, H2, CH4, and C2H6 at pressures for which collisional processes are important. Emission from the CH and OH species are sustained for longer times in the presence of air or O2 and the decay becomes distincly non-exponential. There is also a significant intensity effect which is particularly noticeable for OH which reaches a maximum at a given oxygen pressure. Mixtures af ethanol with O2/Ar result in longer lifetimes for OH whereas in mixtures with CO, C2H6 and C3H6 a significant decrease is observed. In the case af CO, this behavior is assumed ta be due to relaxation processes, while in the latter cases hydrogen abstraction by OH is presumably responsible for the decrease. The presence of the well known scavenger NO had little effect on the rate constants used to describe the emission process. On the other hand, OH emission was completely quenchend in mixtures of the precursor with Cl2. In this case, the observation of CH3Cl by gas chromatography suggests that chemical reaction of some of the primary dissociation fragments inhibits further laser pumping. An attempt to understand the possible mechanism for the formatiun of the transient species was developed through the use of an RRKM calculation of the primary dissociation processes of ethanol under multiphoton excitation. The RRKM calculations were modelled for the H2O elimination, the main process at low pressures, and different bond scission processes which may become important at higher laser intensities. The theoretical calculation clearly shows that H2O elimination is the preferred pathway at lower excitation energies but is rapidly replaced by the other channels at higher energy contents. A similar effect is observed for the complete unimolecular decomposition as a function of pressure, where at the higher pressures, the bond scission processes yielding free radicals are dominant as a consequence of the deactivation of the molecules with threshold energies before they can undergo chemical reaction.

>Magister Scientiae - MSc / Recent research shows that the study of optical properties of organic material natural dyes has gained much consideration. The specific functional groups in several natural dyes remain essential for the large nonlinear absorption expressed in terms of nonlinear optical susceptibilities or other mechanism of absorption such as two photon absorption (TPA), reverse saturable absorption (RSA) or intensitydependent refractive index characteristic. In this thesis we highlight the optical limiting responses of selected natural dyes as nonlinear response in the femtosecond regime. This technique refers to the decrease of the transmittance of the material with the increased incident light intensity.Three dyes derived from beetroot, flame flower and mimosa flower dyes were investigated. The results showed a limiting behaviour around 795 mW for the beetroot and the flame dye while there is total transmission in the flame dye sample. The performance of the nonlinearity i.e. the optical limiting is related to the existence of alternating single and double bonds(i.e. C-C and C=C bonds) in the molecules that provides the material with the electron delocalization, but also it is related to the light intensity.Beside nonlinearity study, crystallographic investigation was carried out for more possible applicability of the selected dyes and this concerned only the mimosa and flame flower dye thin film samples since the beetroot thin film was very sensitive to strong irradiation (i.e. immediately destroyed when exposed to light with high intensity). For more stability,dye solutions were encapsulated in gels for further measurements.

Les microchip lasers à impulsions sub-nanosecondes peuvent être des alternatives intéressantes aux lasers à impulsions femtosecondes pour le micro-usinage des matériaux transparents par absorption multiphotonique. Ces lasers peuvent facilement atteindre les puissances crêtes nécessaires pour déclencher l'ablation de tous les matériaux, y compris les diamants, céramiques, plastiques, et des verres. En outre, ils sont de faible coût, avec un design compact et robuste. Dans cette thèse, un micro-chip laser Nd:YAG amplifié (532 nm, 300 ps) a été utilisé pour la micro-gravure et le marquage de différents types de matériaux transparents, comme le verre borosilicate D263, le verre BK7 et le thermoplastique SBS. L'analyse des résultats a montré un bon accord avec le modèle d'expulsion de matière suite à la génération d'un plasma provoqué par une absorption laser à deux photons. Une résolution sub-micronique de marquage a été obtenue à l'intérieur d'un verre de borosilicate. Des canaux microfluidiques pour capteurs optiques ont été gravés sur verre BK-7 comprenant des guides d'ondes réalisés par échange d'ionique. Des réseaux denses de micro-canaux ont été fabriqués à la surface de matériaux thermoplastiques avec une zone affectée par les effets thermiques limités à quelques micromètres. En conclusion, ce travail de thèse montre que l'utilisation de ce type de laser permet un micro-usinage de très haute résolution avec des effets thermiques limités. / Microchip lasers with sub-nanosecond pulses are attractive alternative to femtosecond lasers for micromachining in transparent materials by multiphoton absorption. These lasers can easily reach pulse peak powers that are needed to trigger ablation in all materials, including diamond, ceramics, plastics, and glasses. In addition, they are low cost with compact and rugged design. In this thesis, a microchip laser (532 nm, 300 ps) has been used for micro-engraving and marking different types of transparent materials such as borosilicate D263, BK7, and SBS thermoplastic. Experimental resultsare rationalized by the model of matter explosion following the plasma generation induced by the laser two-photon absorption. Sub-micron resolution embedded marking is demonstrated inside borosilicate glass. Micro fluidic channels for optical sensors are engraved on BK-7 glass with ion-doped waveguides. Arrays of dense micro channels are fabricated at the surface of thermoplastics with a zone affected by thermal effects limited to the micron range. In summary, this thesis demonstrates that this type of laser can be efficiently used for high-resolution micro-machining transparent materials with minimal thermal effects.

O desenvolvimento da fotônica integrada vem recebendo muita atenção nos últimos anos. Sua alta funcionalidade e velocidade de transmissão de sinais possibilitam a aplicação em diversas áreas, que vão desde comunicações até biologia. O uso de polímeros em circuitos fotônicos integrados tem se mostrado interessante, pois compostos orgânicos podem ser facilmente incorporados a matrizes poliméricas. Isso faz com que as propriedades físicas do polímero possam ser modificadas de acordo com os materiais incorporados. Além disso, a técnica da fotopolimerização por absorção de dois fótons torna possível a produção de microestruturas poliméricas tridimensionais com alta resolução. A incorporação dessas microestruturas a circuitos fotônicos pode trazer um novo ramo de funcionalidades devido à facilidade de modificação das propriedades dos polímeros. Além disso, a tridimensionalidade das estruturas permite a realização de conexões ópticas em três dimensões, o que colabora para o aumento da compacticidade dos dispositivos fotônicos. No entanto, para que estas microestruturas possam ser efetivamente incorporadas aos circuitos fotônicos é necessário desenvolver formas de conectá-las a fontes externas de excitação, bem como a instrumentos de análise de sinais. Os tapers de fibras ópticas, também conhecidos como microfibras ou nanofibras, são bons candidatos para realizar essa tarefa devido a suas dimensões reduzidas, as quais são compatíveis com o tamanho das microestruturas. Neste trabalho desenvolvemos métodos para realizar a conexão óptica entre microestruturas poliméricas e tapers de fibras ópticas. As microestruturas foram produzidas através da técnica de fotopolimerização por absorção de dois fótons e corantes orgânicos foram incorporados à matriz polimérica para conferir propriedades fluorescentes às estruturas. Os tapers foram produzidos a partir de fibras ópticas convencionais por uma técnica de aquecimento e estiramento. Para realizar a conexão óptica, dois métodos foram desenvolvidos. No primeiro deles as microestruturas foram excitadas através de uma lente objetiva e sua emisão foi coletada por um taper. No segundo método, tanto a excitação quanto a coleta foram realizadas por tapers de fibras ópticas. Em ambos os casos as fibras foram posicionadas através de micromanipuladores. Os resultados obtidos indicam que os tapers são ferramentas adequadas para realizar tanto a excitação quando a coleta da emissão de microestruturas, pois permitem excitação individual e coleta localizada. Produzimos microestruturas com múltiplas dopagens e pudemos concluir que a excitação localizada de diferentes partes da estrutura, bem como a correta escolha do comprimento de onda de excitação, são mecanismos que levam a alterações no espectro de emissão, o que torna estas estruturas candidatas a fontes de luz sintonizáveis que podem ser incorporadas a dispositivos on-chip. Por fim, desenvolvemos um método de produção de microestruturas conectadas a tapers. Este trabalho abre caminho para a incorporação de microestruturas poliméricas a circuitos fotônicos e demonstra que tapers de fibras ópticas são ferramentas eficientes para a realização de microconexões ópticas. / The development of integrated photonics has received a great deal of attention in the last few years. Its high functionality and signal transmission speed allow applications in several fields, from telecommunications to biology. The use of polymeric platforms in integrated photonic circuits is interesting because organic compounds can be easily incorporated to polymeric matrixes, which makes it easy to change the physical properties of the polymer according to the embed materials. Furthermore, the two-photon polymerization technique allows the production of three-dimensional polymeric microstructures with high resolution. The incorporation of these microstructures to photonic circuits paves the way for a new field of funcionalities due to the ease of modification of the polymers properties. Besides that, the structures three-dimensionality allows the performance of optical connections in three dimensions, which can improve the compacticity of the photonic devices. However, for the effective incorporation of these microstructures to photonic circuits, it is necessary to develop ways to connect them to external excitation sources, as well as analysis instruments. Optical fiber tapers, also known as microfibers or nanofibers, are good candidates for this task due to their reduced dimensions that are compatible with the size of the microstructures. In this work we developed methods for the performance of optical connections of polymeric microstructures through fiber tapers. The microstrutures were produced through the two-photon polymerization technique and organic dyes were incorporated to the polymeric matrix in order to introduce fluorescent properties. The fiber tapers were produced from conventional optical fibers through a heat-and-draw approach. To perform the optical connections, two methods were developed. In the first one, the microestructures were excited through a microscope objective and emission collection was performed by a fiber taper. In the second approach, excitation and collection were performed by fiber tapers. In both methods, the tapers were set up by micromanipulators. The obtained results indicate that tapers are a suitable tool to perform optical excitation and emission collection in microstructures, as they allow individual excitation and localized collection. Multiple doped microstructures were produced and we could imply that the localized excitation of different parts of the structures, as well as the correct choice of the excitation wavelength, are tools that lead to changes in the emission spectrum, which makes these structures candidates to tunable light sources that can be incorporated to on-chip devices. At last, we developed a method for the production of microstructures connected to fiber tapers. This work paves the way for the incorporation of polymeric microstructures to photonics circuits and demonstrates that fiber tapers are efficient tools to perform optical microconnections.