Three-dimensional microfabrication with two-photon-absorbed photopolymerization

Maruo, Shoji; Nakamura, Osamu; Kawata, Satoshi

doi:10.1364/ol.22.000132

Cited by 1,753 publications

(918 citation statements)

References 8 publications

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“…Depending on the nature of this coupling, the ground state or the excited state may be either localized or delocalized, and specific optical properties may be either enhanced or suppressed. 44 Among the many NLO effects, two-photon absorption (TPA) has become very popular during the past decade owing to its wide-ranging applications such as two-photon laser scanning microscopy, [45][46][47] photodynamic therapy, 48 optical power limitation, 4,5 microfabrication, [49][50][51][52] or 3D optical data storage. [53][54][55][56] Depending on the applications, two-photon chromophores have to satisfy different kinds of requirements.…”

Section: Introductionmentioning

confidence: 99%

Effects of (Multi)branching of Dipolar Chromophores on Photophysical Properties and Two-Photon Absorption

et al. 2005

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To investigate the effect of branching on linear and nonlinear optical properties, a specific series of chromophores, epitome of (multi)branched dipoles, has been thoroughly explored by a combined theoretical and experimental approach. Excited-state structure calculations based on quantum-chemical techniques (timedependent density functional theory) as well as a Frenkel exciton model nicely complement experimental photoluminescence and one-and two-photon absorption findings and contribute to their interpretation. This allowed us to get a deep insight into the nature of fundamental excited-state dynamics and the nonlinear optical (NLO) response involved. Both experiment and theory reveal that a multidimensional intramolecular charge transfer takes place from the donating moiety to the periphery of the branched molecules upon excitation, while fluorescence stems from an excited state localized on one of the dipolar branches. Branching is also observed to lead to cooperative enhancement of two-photon absorption (TPA) while maintaining high fluorescence quantum yield, thanks to localization of the emitting state. The comparison between results obtained in the Frenkel exciton scheme and ab initio results suggests the coherent coupling between branches as one of the possible mechanisms for the observed enhancement. New strategies for the rational design of NLO molecular assemblies are thus inferred on the basis of the acquired insights.

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Section: Introductionmentioning

confidence: 99%

Effects of (Multi)branching of Dipolar Chromophores on Photophysical Properties and Two-Photon Absorption

et al. 2005

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“…1 In fact, two-photon absorption (TPA) opens the way for both improved and novel technological capabilities, such as multiphoton microscopy, 2,3 optical limiting, 4,5 and microfabrication. [6][7][8] In the search for adequate materials for the various applications, organic molecular systems are of particularly interest due to their inherent modularity and the potentially high TPA response of conjugated systems. Indeed, over the past decade, an increasing effort has been devoted to the design of chromophores with enhanced TPA responses progressively moving from monomeric chromophores such as dipoles [9][10][11][12][13][14][15] and quadrupoles 4,5,11, toward multimeric complex molecular architectures.…”

Section: Introductionmentioning

confidence: 99%

Two-Photon Transitions in Quadrupolar and Branched Chromophores: Experiment and Theory

et al. 2007

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A combined experimental and theoretical study is conducted on a series of model compounds in order to assess the combined role of branching and charge symmetry on absorption, photoluminescence, and twophoton absorption (TPA) properties. The main issue of this study is to examine how branching of quadrupolar chomophores can lead to different consequences as compared to branching of dipolar chromophores. Hence, three structurally related π-conjugated quadrupolar chromophores symmetrically substituted with donor end groups and one branched structure built from the assembly of three quadrupolar branches via a common donor moiety are used as model compounds. Their photophysical properties are studied using UV-vis spectroscopy, and the TPA spectra are determined through two-photon excited fluorescence experiments using femtosecond pulses in the 500-1000 nm range. Experimental studies are complemented by theoretical calculations. The applied theoretical methodology is based on time-dependent density functional theory, the Frenkel exciton model, and analysis in terms of the natural transition orbitals of relevant electronic states. Theory reveals that a symmetrical intramolecular charge transfer from the terminal donating groups to the middle of the molecule takes place in all quadrupolar chromophores upon photoexcitation. In contrast, branching via a central electron-donating triphenylamine moiety breaks the quadrupolar symmetry of the branches. Consequently, all Frank-Condon excited states have significant asymmetric multidimensional charge-transfer character upon excitation. Subsequent vibrational relaxation of the branched chromophore in the excited state leads to a localization of the excitation and fluorescence stemming from a single branch. As opposed to what was earlier observed when dipolar chromophores are branched via the same common electron-donating moiety, we find only a slight enhancement of the maximum TPA response of the branched compound with respect to an additive contribution of its quadrupolar branches. In contrast, substantial modifications of the spectral shape are observed. This is attributed to the subtle interplay of interbranch electronic coupling and asymmetry caused by branching.

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“…[3] Esta técnica de microfabricação tem se destacado no meio científico devido a sua capacidade de produzir microestruturas tridimensionais de alta complexidade e variedade de formas, permitindo até mesmo a confecção de estruturas contendo partes móveis. [4,5] A FA2F consiste em focalizar um feixe pulsado de femtossegundos no volume de uma resina polimérica contendo um fotoiniciador, composto orgânico responsável por desencadear a reação de polimerização quando excitado via absorção de dois fótons.…”

Section: Aplicaçãounclassified

Desenvolvimento de um obturador de feixe óptico utilizando um disco rígido de computador

Tomázio

Romero

Mendonça

2017

Rev. Bras. Ensino Fís.

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O objetivo deste trabalho é demonstrar a confecção de um obturador de feixe óptico a partir de um disco rígido de computador. O controle de corrente do dispositivo é feito por modulação de largura de pulso (Pulse width modulation - PWM), uma técnica que permite variar níveis de tensão/corrente por meio do ajuste da largura de pulso de um sinal digital. Este controle é feito de forma a minimizar a potência dissipada no dispositivo, aumentando assim sua vida útil. O núcleo do circuito de controle de corrente é o Arduino Uno, uma placa de microcontrolador de baixo custo e de fácil programação, amplamente utilizado como plataforma para prototipagem eletrônica. Por fim, a título de ilustração, apresentamos o uso do obturador de feixe óptico desenvolvido em um sistema de microfabricação via fotopolimerização por absorção de dois fótons, no qual ele tem papel fundamental.

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Three-dimensional microfabrication with two-photon-absorbed photopolymerization

Cited by 1,753 publications

References 8 publications

Effects of (Multi)branching of Dipolar Chromophores on Photophysical Properties and Two-Photon Absorption

Effects of (Multi)branching of Dipolar Chromophores on Photophysical Properties and Two-Photon Absorption

Two-Photon Transitions in Quadrupolar and Branched Chromophores: Experiment and Theory

Desenvolvimento de um obturador de feixe óptico utilizando um disco rígido de computador

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