Multiphoton fabrication of freeform polymer microstructures with gold nanorods

ArticleinOptics Express 18(26):27550-9 · December 2010with7 Reads
DOI: 10.1364/OE.18.027550 · Source: PubMed
Abstract
In this study, three-dimensional (3D) polyacrylamide microstructures containing gold nanorods (AuNRs) were fabricated by two-photon polymerization (TPP) using Rose Bengal (RB) as the photoinitiator. To retain AuNRs in the 3D polymer microstructures, the laser wavelength was chosen for two-photon RB absorption for improved TPP efficiency, but not for enhancing the longitudinal plasmon resonance of AuNRs which may result in photothermal damage of AuNRs. After TPP processing, the laser wavelength was tuned for the longitudinal plasmon resonance and the laser power was increased to beyond the damage threshold of the AuNRs for reshaping the AuNRs into gold nanospheres. As a result, AuNRs in designated positions of the fabricated 3D microstructures can be achieved. Two-photon luminescence from the doped AuNRs can also act as contrast agent for the visualization of 3D polymer microstructures.
    • "Over the last two decades, the femtosecond (fs) pulse laser has become a versatile tool in a variety of applications [1,2]. The high peak power of the ultra-short pulse and tight focusing by a high numerical aperture objective lens are critical for inducing sufficient multiphoton absorption (MPA) to achieve high precision fabrication345. Further, when the fs laser peak power is high enough, this nonlinear process, together with cascade ionization, generates very high concentrations of free electrons in the focal volume, resulting in plasma-mediated ablation [6]. Plasma-mediated ablation is a reaction in which the energy level is high enough to tear molecules apart, rather than just drive the electronic transitions that lead to fluorescent relaxation. "
    [Show abstract] [Hide abstract] ABSTRACT: In this study, a developed temporal focusing-based femtosecond laser system provides high-throughput multiphoton-induced reduction and ablation of graphene oxide (GO) films. Integrated with a digital micromirror device to locally control the laser pulse numbers, GO-based micropatterns can be quickly achieved instantly. Furthermore, the degree of reduction and ablation can be precisely adjusted via controlling the laser wavelength, power, and pulse number. Compared to point-by-point scanning laser direct writing, this approach offers a high-throughput and multiple-function approach to accomplish a large area of micro-scale patterns on GO films. The high-throughput micropatterning of GO via the temporal focusing-based femtosecond laser system fulfills the requirement of mass production for GO-based applications in microelectronic devices.
    Full-text · Article · Aug 2014
    • "The microstructures were obtained by two-photon polymerization (2PP), a technique that allows the fabrication of complex 3D topologies with no intrinsic constraints [11,12] and resolution bellow the diffraction limit12131415. Furthermore, by doping the resin used for 2PP with distinct compounds, some groups have achieved microstructures with interesting optical, biological and electrical properties1617181920. The azopolymer-doped microstructures fabricated present birefringence when excited by an Ar + laser operating at 514.5 nm. "
    [Show abstract] [Hide abstract] ABSTRACT: Birefringent materials have many applications in optical devices. An approach to obtain optically induced birefringence is to employ a guest-host strategy, using a polymer matrix containing an azodye. However, such method normally leads to low residual birefringence. Therefore, methodologies to produce microstructures with optimized birefringence are still on demand. Here we report on the fabrication, using two-photon polymerization, and characterization of birefringent microstructures produced in a polymer blend containing an azopolymer. Such microstructures present good structural integrity and residual birefringence of approximately 35 percent, depending on the sample formulation used, which indicates this approach for the fabrication of microoptical devices. (C) 2012 Optical Society of America
    Full-text · Article · Jan 2013
    • "Neos, USA), photomultiplier tubes (PMTs) (H5783P, Hamamatsu, Japan), and a data acquisition (DAQ) card with a field-programmable gate array (FPGA) module (PCI-7831R, National Instruments, USA). A detailed description of the multiphoton fabrication instrument can be found in our previous studies [7,19]. For FLIM, the TCSPC module (PicoHarp 300, PicoQuant) is integrated into the main Proc. of SPIE Vol. "
    [Show abstract] [Hide abstract] ABSTRACT: The two-photon excited fluorescence (TPEF) increments of two dyes via bovine serum albumin (BSA) microstructures fabricated by the two-photon crosslinking technique were investigated. One is Rose Bengal (RB) with a high nonradiative decay rate, while the other is Eosin Y with a low non-radiative decay rate. Experimental results demonstrate that the quantum yield and lifetime of RB are both augmented via crosslinked BSA microstructures. Compared with theoretical analysis, this result indicates that the non-radiative decay rate of RB is decreased; hence, the quenched effect induced by BSA solution is suppressed. However, the fluorescence lifetime of Eosin Y is acutely abated despite the augmented quantum yield for the two-photon crosslinking processing from BSA solution. This result deduces that the radiative decay rate increased. Furthermore, the increased TPEF intensity and lifetime of RB correlated with the concentration of fabricated crosslinked BSA microstructures through pulse selection of the employed femtosecond laser is demonstrated and capable of developing a zone-plate-like BSA microstructure.
    Conference Paper · Sep 2012
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