The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Katsumi Midorikawa - One of the best experts on this subject based on the ideXlab platform.
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Ship-in-a-bottle biomicrochips fabricated by hybrid femtosecond laser processing
MATEC Web of Conferences, 2013Co-Authors: Koji Sugioka, Katsumi MidorikawaAbstract:We demonstrate fabrication of highly functional biomicrochips by hybrid femtosecond laser processing. In this process, 3D microfluidic structures are first formed inside Photosensitive Glass by femtosecond laser direct writing followed by thermal treatment and successive chemical wet etching. Then, functional microcomponents are integrated inside the fabricated microfluidic structures by two-photon photopolyerization. We term the fabricated microchips ship-in-a-bottle biomicrochips,
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three dimensionally embedded indium tin oxide ito films in Photosensitive Glass a transparent and conductive platform for microdevices
Applied Physics A, 2011Co-Authors: Szabolcs Beke, Koji Sugioka, Katsumi Midorikawa, László Kőrösi, Imre DékányAbstract:A new method for embedding transparent and conductive two- and three-dimensional microstructures in Glass is presented. We show that the internal surface of hollow structures fabricated by femtosecond-laser direct writing inside the Photosensitive Glass can be coated by indium tin oxide (Sn-doped In2O3, ITO) using a sol-gel process. The idea of combining two transparent materials with different electrical properties, i.e., insulating and conductive, is very promising and hence it opens new prospects in manufacturing cutting edge microdevices, such as lab-on-a-chips (LOCs) and microelectromechanical systems (MEMS).
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three dimensional femtosecond laser micromachining of Photosensitive Glass for biomicrochips
Laser & Photonics Reviews, 2010Co-Authors: Koji Sugioka, Yasutaka Hanada, Katsumi MidorikawaAbstract:Internal modification of transparent materials such as Glass can be carried out using multiphoton absorption induced by a femtosecond (fs) laser. The fs-laser modification followed by thermal treatment and successive chemical wet etching in a hydrofluoric (HF) acid solution forms three-dimensional (3D) hollow microstructures embedded in Photosensitive Glass. This technique is a powerful method for directly fabricating 3D microfluidic structures inside a Photosensitive Glass microchip. We used fabricated microchips, referred to as a nanoaquarium, for dynamic observations of living microorganisms. In addition, the present technique can also be used to form microoptical components such as micromirrors and microlenses inside the Photosensitive Glass, since the fabricated structures have optically flat surfaces. The integration of microfluidics and microoptical components in a single Glass chip yields biophotonic microchips, in other words, optofluidics, which provide high sensitivity in absorption and fluorescence measurements of small volumes of liquid samples.
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Fabrication of 3D microoptical lenses in Photosensitive Glass using femtosecond laser micromachining
Applied Physics A, 2006Co-Authors: Y. Cheng, Koji Sugioka, H.l. Tsai, Katsumi MidorikawaAbstract:We describe the fabrication of microoptical cylindrical and hemispherical lenses vertically embedded in a Photosensitive Foturan Glass by femtosecond (fs) laser three-dimensional (3D) micromachining. The process is mainly composed of four steps: (1) fs laser scanning in the Photosensitive Glass to form curved surfaces (spherical and/or cylindrical); (2) postannealing of the sample for modification of the exposed areas; (3) chemical etching of the sample for selective removal of the modified areas; and (4) a second postannealing for smoothening the surfaces of the tiny lenses. We examine the focusing ability of the microoptical lenses using a He-Ne laser beam, showing the great potential of using these microoptical lenses in lab-on-a-chip applications.
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Investigation of photoreaction mechanism of Photosensitive Glass by femtosecond laser
Journal of Applied Physics, 2005Co-Authors: Tomohiro Hongo, Koji Sugioka, Ya Cheng, Hiroyuki Niino, Masashi Masuda, Iwao Miyamoto, Hiroshi Takai, Katsumi MidorikawaAbstract:A high-intensity femtosecond (fs) laser can fabricate complicated three-dimensional microstructures inside Photosensitive Glass with high spatial resolution. In this work, the mechanism of the photoreaction of the Photosensitive Glass to the infrared fs laser is investigated. We examine the photoinduced electron excitation process on the basis of the determination of the critical dose and a change of the optical-absorption spectrum after the fs laser irradiation. The photoreaction mechanism is discussed in comparison with the case of an ultraviolet nanosecond laser irradiation. Finally, the successive interband electron excitation through defect levels by multiphoton absorption is proposed.
Koji Sugioka - One of the best experts on this subject based on the ideXlab platform.
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Picosecond Laser Processing of Photosensitive Glass for Generation of Biologically Relevant Microenvironments
Applied Sciences, 2020Co-Authors: Florin Jipa, Stefana Orobeti, Cristian Butnaru, Marian Zamfirescu, Emanuel Axente, Felix Sima, Koji SugiokaAbstract:Various material processing techniques have been proposed for fabrication of smart surfaces that can modulate cellular behavior and address specific clinical issues. Among them, laser-based technologies have attracted growing interest due to processing versatility. Latest development of ultrashort pulse lasers with pulse widths from several tens of femtoseconds (fs) to several picoseconds (ps) allows clean microfabrication of a variety of materials at micro- and nanoscale both at surface and in volume. In this study, we addressed the possibility of 3D microfabrication of Photosensitive Glass (PG) by high repetition rate ps laser-assisted etching (PLAE) to improve the fabrication efficiency for the development of useful tools to be used for specific biological applications. Microfluidic structures fabricated by PLAE should provide the flow aspects, 3D characteristics, and possibility of producing functional structures to achieve the biologically relevant microenvironments. Specifically, the microfluidic structures could induce cellular chemotaxis over extended periods in diffusion-based gradient media. More importantly, the 3D characteristics could reproduce capillaries for in vitro testing of relevant organ models. Single cell trapping and analysis by using the fabricated microfluidic structures are also essential for understanding individual cell behavior within the same population. To this end, this paper demonstrates: (1) generation of 3D structures in Glass volume or on surface for fabrication of microfluidic channels, (2) subtractive 3D surface patterning to create patterned molds in a controlled manor for casting polydimethylsiloxane (PDMS) structures and developing single cell microchambers, and (3) designing Glass photo-masks to be used for sequel additive patterning of biocompatible nanomaterials with controlled shapes, sizes, and periodicity. Mesenchymal stem cells grown on laser-processed Glass surfaces revealed no sign of cytotoxicity, while a collagen thin coating improved cellular adhesion.
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Ship-in-a-bottle biomicrochips fabricated by hybrid femtosecond laser processing
MATEC Web of Conferences, 2013Co-Authors: Koji Sugioka, Katsumi MidorikawaAbstract:We demonstrate fabrication of highly functional biomicrochips by hybrid femtosecond laser processing. In this process, 3D microfluidic structures are first formed inside Photosensitive Glass by femtosecond laser direct writing followed by thermal treatment and successive chemical wet etching. Then, functional microcomponents are integrated inside the fabricated microfluidic structures by two-photon photopolyerization. We term the fabricated microchips ship-in-a-bottle biomicrochips,
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Microstructuring of Photosensitive Glass
Topics in Applied Physics, 2011Co-Authors: Koji SugiokaAbstract:Femtosecond laser direct writing followed by thermal treatment and successive wet etching can form three-dimensional (3D) hollow microstructures inside Photosensitive Glass. The principles and procedures of this process are explained. Next, the fabrication of 3D microfluidic structures and optical microcomponents is reviewed. Finally, the manufacture of functional microchip devices such as a microfluidic dye laser, optofluidics, and a nano-aquarium by integrating the microcomponents in a single Glass chip is demonstrated.
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three dimensionally embedded indium tin oxide ito films in Photosensitive Glass a transparent and conductive platform for microdevices
Applied Physics A, 2011Co-Authors: Szabolcs Beke, Koji Sugioka, Katsumi Midorikawa, László Kőrösi, Imre DékányAbstract:A new method for embedding transparent and conductive two- and three-dimensional microstructures in Glass is presented. We show that the internal surface of hollow structures fabricated by femtosecond-laser direct writing inside the Photosensitive Glass can be coated by indium tin oxide (Sn-doped In2O3, ITO) using a sol-gel process. The idea of combining two transparent materials with different electrical properties, i.e., insulating and conductive, is very promising and hence it opens new prospects in manufacturing cutting edge microdevices, such as lab-on-a-chips (LOCs) and microelectromechanical systems (MEMS).
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three dimensional femtosecond laser micromachining of Photosensitive Glass for biomicrochips
Laser & Photonics Reviews, 2010Co-Authors: Koji Sugioka, Yasutaka Hanada, Katsumi MidorikawaAbstract:Internal modification of transparent materials such as Glass can be carried out using multiphoton absorption induced by a femtosecond (fs) laser. The fs-laser modification followed by thermal treatment and successive chemical wet etching in a hydrofluoric (HF) acid solution forms three-dimensional (3D) hollow microstructures embedded in Photosensitive Glass. This technique is a powerful method for directly fabricating 3D microfluidic structures inside a Photosensitive Glass microchip. We used fabricated microchips, referred to as a nanoaquarium, for dynamic observations of living microorganisms. In addition, the present technique can also be used to form microoptical components such as micromirrors and microlenses inside the Photosensitive Glass, since the fabricated structures have optically flat surfaces. The integration of microfluidics and microoptical components in a single Glass chip yields biophotonic microchips, in other words, optofluidics, which provide high sensitivity in absorption and fluorescence measurements of small volumes of liquid samples.
Szabolcs Beke - One of the best experts on this subject based on the ideXlab platform.
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3D Photoelectrode for Dye Solar Cells Realized by Laser Micromachining of Photosensitive Glass
The Journal of Physical Chemistry C, 2014Co-Authors: Michele Manca, Szabolcs Beke, Luisa De Marco, Paola Pareo, Antonio Qualtieri, Alessandro Cannavale, Fernando Brandi, Giuseppe GigliAbstract:An explorative dye solar cell architecture based on the implementation of a 3D micropatterned photoelectrode is disclosed here. An array of conical micropillars has been realized by laser micromachining of Photosensitive Glass which has been advantageously used as a substrate for deposition of a thin transparent conductive layer and a thick mesoporous TiO2 electrode. A significantly higher photocurrent density has been detected as an effect of the extended overall absorbing area of the micropatterned photoelectrode with respect to a conventional 2D reference photoelectrode. This enhancement can also be partially imputable to a not negligible “waveguide effect” occurring within the Glass micropillars
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Highly transparent ITO thin films on Photosensitive Glass: sol–gel synthesis, structure, morphology and optical properties
Applied Physics A, 2012Co-Authors: László Kőrösi, Szilvia Papp, Szabolcs Beke, Béla Pécz, Róbert Horváth, Péter Petrik, Emil Agócs, Imre DékányAbstract:Conductive and highly transparent indium tin oxide (ITO) thin films were prepared on Photosensitive Glass substrates by the combination of sol–gel and spin-coating techniques. First, the substrates were coated with amorphous Sn-doped indium hydroxide, and these amorphous films were then calcined at 550^∘C to produce crystalline and electrically conductive ITO layers. The resulting thin films were characterized by means of scanning electron microscopy, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The measurements revealed that the ITO films were composed of spherical crystallites around 20 nm in size with mainly cubic crystal structure. The ITO films acted as antireflection coatings increasing the transparency of the coated substrates compared to that of the bare supports. The developed ITO films with a thickness of ∼170–330 nm were highly transparent in the visible spectrum with sheet resistances of 4.0–13.7 kΩ/sq. By coating Photosensitive Glass with ITO films, our results open up new perspectives in micro- and nano-technology, for example in fabricating conductive and highly transparent 3D microreactors.
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highly transparent ito thin films on Photosensitive Glass sol gel synthesis structure morphology and optical properties
Applied Physics A, 2012Co-Authors: László Kőrösi, Szilvia Papp, Szabolcs Beke, Béla Pécz, Róbert Horváth, Péter Petrik, Emil Agócs, Imre DékányAbstract:Conductive and highly transparent indium tin oxide (ITO) thin films were prepared on Photosensitive Glass substrates by the combination of sol–gel and spin-coating techniques. First, the substrates were coated with amorphous Sn-doped indium hydroxide, and these amorphous films were then calcined at 550∘C to produce crystalline and electrically conductive ITO layers. The resulting thin films were characterized by means of scanning electron microscopy, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The measurements revealed that the ITO films were composed of spherical crystallites around 20 nm in size with mainly cubic crystal structure. The ITO films acted as antireflection coatings increasing the transparency of the coated substrates compared to that of the bare supports. The developed ITO films with a thickness of ∼170–330 nm were highly transparent in the visible spectrum with sheet resistances of 4.0–13.7 kΩ/sq. By coating Photosensitive Glass with ITO films, our results open up new perspectives in micro- and nano-technology, for example in fabricating conductive and highly transparent 3D microreactors.
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three dimensionally embedded indium tin oxide ito films in Photosensitive Glass a transparent and conductive platform for microdevices
Applied Physics A, 2011Co-Authors: Szabolcs Beke, Koji Sugioka, Katsumi Midorikawa, László Kőrösi, Imre DékányAbstract:A new method for embedding transparent and conductive two- and three-dimensional microstructures in Glass is presented. We show that the internal surface of hollow structures fabricated by femtosecond-laser direct writing inside the Photosensitive Glass can be coated by indium tin oxide (Sn-doped In2O3, ITO) using a sol-gel process. The idea of combining two transparent materials with different electrical properties, i.e., insulating and conductive, is very promising and hence it opens new prospects in manufacturing cutting edge microdevices, such as lab-on-a-chips (LOCs) and microelectromechanical systems (MEMS).
Imre Dékány - One of the best experts on this subject based on the ideXlab platform.
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Highly transparent ITO thin films on Photosensitive Glass: sol–gel synthesis, structure, morphology and optical properties
Applied Physics A, 2012Co-Authors: László Kőrösi, Szilvia Papp, Szabolcs Beke, Béla Pécz, Róbert Horváth, Péter Petrik, Emil Agócs, Imre DékányAbstract:Conductive and highly transparent indium tin oxide (ITO) thin films were prepared on Photosensitive Glass substrates by the combination of sol–gel and spin-coating techniques. First, the substrates were coated with amorphous Sn-doped indium hydroxide, and these amorphous films were then calcined at 550^∘C to produce crystalline and electrically conductive ITO layers. The resulting thin films were characterized by means of scanning electron microscopy, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The measurements revealed that the ITO films were composed of spherical crystallites around 20 nm in size with mainly cubic crystal structure. The ITO films acted as antireflection coatings increasing the transparency of the coated substrates compared to that of the bare supports. The developed ITO films with a thickness of ∼170–330 nm were highly transparent in the visible spectrum with sheet resistances of 4.0–13.7 kΩ/sq. By coating Photosensitive Glass with ITO films, our results open up new perspectives in micro- and nano-technology, for example in fabricating conductive and highly transparent 3D microreactors.
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highly transparent ito thin films on Photosensitive Glass sol gel synthesis structure morphology and optical properties
Applied Physics A, 2012Co-Authors: László Kőrösi, Szilvia Papp, Szabolcs Beke, Béla Pécz, Róbert Horváth, Péter Petrik, Emil Agócs, Imre DékányAbstract:Conductive and highly transparent indium tin oxide (ITO) thin films were prepared on Photosensitive Glass substrates by the combination of sol–gel and spin-coating techniques. First, the substrates were coated with amorphous Sn-doped indium hydroxide, and these amorphous films were then calcined at 550∘C to produce crystalline and electrically conductive ITO layers. The resulting thin films were characterized by means of scanning electron microscopy, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. The measurements revealed that the ITO films were composed of spherical crystallites around 20 nm in size with mainly cubic crystal structure. The ITO films acted as antireflection coatings increasing the transparency of the coated substrates compared to that of the bare supports. The developed ITO films with a thickness of ∼170–330 nm were highly transparent in the visible spectrum with sheet resistances of 4.0–13.7 kΩ/sq. By coating Photosensitive Glass with ITO films, our results open up new perspectives in micro- and nano-technology, for example in fabricating conductive and highly transparent 3D microreactors.
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three dimensionally embedded indium tin oxide ito films in Photosensitive Glass a transparent and conductive platform for microdevices
Applied Physics A, 2011Co-Authors: Szabolcs Beke, Koji Sugioka, Katsumi Midorikawa, László Kőrösi, Imre DékányAbstract:A new method for embedding transparent and conductive two- and three-dimensional microstructures in Glass is presented. We show that the internal surface of hollow structures fabricated by femtosecond-laser direct writing inside the Photosensitive Glass can be coated by indium tin oxide (Sn-doped In2O3, ITO) using a sol-gel process. The idea of combining two transparent materials with different electrical properties, i.e., insulating and conductive, is very promising and hence it opens new prospects in manufacturing cutting edge microdevices, such as lab-on-a-chips (LOCs) and microelectromechanical systems (MEMS).
Ya Cheng - One of the best experts on this subject based on the ideXlab platform.
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Hybrid Integration in Photosensitive Glass Using 3D Femtosecond Laser Micromachining and Its Commercial Potential
First International Conference on Integration and Commercialization of Micro and Nanosystems Parts A and B, 2007Co-Authors: Ya ChengAbstract:By shrinking a roomful of laboratory equipments and packing them into a palm-size chip, single Lab-on-a-chip devices are capable of performing a variety of chemical and biological analyses with reduction of reagent consumption, waste production, analysis time and labor cost. However, difficulties in packaging and assembly have been major challenging issues in the manufacture of Lab-on-a-chip devices. To tackle this problem, we recently combined the 3D femtosecond (fs) laser microfabrication technique and the multifunctionality of a Photosensitive Glass called Foturan. This development enables us to form various true 3D hollow microstructures inside or on the surface of Foturan Glass with one continuous processing. Using this technique, a variety of micro-chemical reactor structures, including microchannels, microchambers, and microvalves, have been fabricated inside Foturan Glass with an approximate spatial resolution of 10μm. Since the microstructuring of Foturan Glass by fs laser is a non-ablative photochemistry processing, the fabricated internal surface is smooth and free of debris and cracks. The smooth surfaces can thus be used as microoptical elements to effectively reflect/deflect light beams. For the purpose of further smoothening the etched internal surface, we applied an additional annealing to the samples after etching by which the average roughness was brought down to ∼0.8nm on the laser scanned surface. Thus, we are able to fabricate microoptical mirrors, micro-beam splitters, freestanding optical fibers, and microoptical lenses in the Glass. We have also demonstrated the functions of all these structures using a He-Ne laser. Functional micro-devices such as microfluidic dye lasers were successfully fabricated by integrating the microoptical and microfluidic components inside the Glass, and lasing action was confirmed by analyzing the emission spectra at different pumping powers. The commercial potential of this technique is also discussed in this paper.Copyright © 2007 by ASME
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Investigation of photoreaction mechanism of Photosensitive Glass by femtosecond laser
Journal of Applied Physics, 2005Co-Authors: Tomohiro Hongo, Koji Sugioka, Ya Cheng, Hiroyuki Niino, Masashi Masuda, Iwao Miyamoto, Hiroshi Takai, Katsumi MidorikawaAbstract:A high-intensity femtosecond (fs) laser can fabricate complicated three-dimensional microstructures inside Photosensitive Glass with high spatial resolution. In this work, the mechanism of the photoreaction of the Photosensitive Glass to the infrared fs laser is investigated. We examine the photoinduced electron excitation process on the basis of the determination of the critical dose and a change of the optical-absorption spectrum after the fs laser irradiation. The photoreaction mechanism is discussed in comparison with the case of an ultraviolet nanosecond laser irradiation. Finally, the successive interband electron excitation through defect levels by multiphoton absorption is proposed.
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3D microstructuring and selective metallization of Photosensitive Glass by photochemical reaction using femtosecond laser
International Congress on Applications of Lasers & Electro-Optics, 2004Co-Authors: Koji Sugioka, Ya Cheng, Katsumi MidorikawaAbstract:3D microstructuring of Photosensitive Glass is demonstrated by photochemical reaction using femtosecond (fs) laser for lab-on-chip application. True 3D hollow microstructures embedded in the Glass are fabricated by the fs laser direct write followed by heat treatment and successive wet etching. Modification mechanism of the Photosensitive Glass by the fs laser attributed to the photochemical reaction is discussed. Advantages of the photochemical reaction are to reduce laser fluence and to enhance scanning speed compared with conventional fs laser processing, resulting in increasing throughput. A variety of lab-on-chip device components like microfluidics, microvalve, microoptics, etc. are fabricated by using this technique. The photochemical reaction of this process is also applied for selective metallization of the Glass for manufacturing the lab-on-chip device.3D microstructuring of Photosensitive Glass is demonstrated by photochemical reaction using femtosecond (fs) laser for lab-on-chip application. True 3D hollow microstructures embedded in the Glass are fabricated by the fs laser direct write followed by heat treatment and successive wet etching. Modification mechanism of the Photosensitive Glass by the fs laser attributed to the photochemical reaction is discussed. Advantages of the photochemical reaction are to reduce laser fluence and to enhance scanning speed compared with conventional fs laser processing, resulting in increasing throughput. A variety of lab-on-chip device components like microfluidics, microvalve, microoptics, etc. are fabricated by using this technique. The photochemical reaction of this process is also applied for selective metallization of the Glass for manufacturing the lab-on-chip device.
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3d micromachining of Photosensitive Glass by femtosecond laser for microreactor manufacture
Journal of Photopolymer Science and Technology, 2004Co-Authors: Koji Sugioka, Ya Cheng, Katsumi MidorikawaAbstract:Three-dimensional (3D) micromachining of Photosensitive Glass is demonstrated by using femtosecond (fs) laser for Lab.-on-chip, in other words, micro total analysis system (μ-TAS), application. The fs laser direct-write process followed by a thermal treatment and successive chemical etching in a HF aqueous solution produces true 3D hollow microstructures embedded in the Photosensitive Glass. This technique is applied for manufacturing a microfluidic structure inside the Glass. Mixing of two kinds of aqueous solutions is demonstrated in the fabricated structure. A freely movable microplate is also fabricated inside Glass to control a stream of reagents in the microfluidics. In the meanwhile, this technique is applied for integrating microoptics like micromirror and micro beam splitter in the Glass chip for optical analysis of reactants produced in the microfluidics.
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Optical gratings embedded in Photosensitive Glass by photochemical reaction using a femtosecond laser.
Optics express, 2003Co-Authors: Ya Cheng, Koji Sugioka, Masashi Masuda, Koichi Toyoda, Kazuhiko Shihoyama, Katsumi MidorikawaAbstract:We describe a new approach to the internal refractive index modification of Glass by a femtosecond (fs) laser. The Glass we used is a Photosensitive Glass Foturan which contains trace amounts of silver. Silver nanoparticles, which is responsible for the refractive index change, can be formed in the Glass after exposed to the fs laser and then postbaked at an appropriate temperature between 500 degrees C and 550 degrees C. In this work, latent images of grating structures are first inscribed into the Photosensitive Glass by photochemical reaction of a tightly focused fs laser beam with an intensity much lower than the threshold of optical breakdown. After this step, no measurable diffraction can be observed by irradiating the gratings with a He-Ne laser beam. The samples are then baked at 520 degrees C for various durations from 3h to 18h. Diffraction of the optical grating embedded in the Glass can now be observed, and the diffraction efficiency increases with postbaking duration, indicating that a refractive index change occurs in the modified regions. The relationship between the refractive index change and the postbaking duration is systematically investigated.