Prof. Jun Yamamoto Profile

Prof. Jun Yamamoto

Professor at Kyoto Univ

SPIE Involvement:

Conference Chair | Editor | Author

Proceedings Article | 13 March 2024 Presentation

Dynamic heterogeneity in nematic liquid crystal gels and glasses observed by the novel fluctuation microscopy

Jun Yamamoto

Proceedings Volume PC12907, PC129070I (2024) https://doi.org/10.1117/12.3001040

KEYWORDS: Liquid crystals, Inhomogeneities, Glasses, Polymers, Polymerization, Optical microscopy, Microscopes, Visualization, Ultraviolet radiation, Microscopy

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Proceedings Article | 14 March 2023 Presentation

Imaging dynamic heterogeneity of soft matter by fluctuation microscopy (Conference Presentation)

Jun Yamamoto

Proceedings Volume PC12442, PC1244204 (2023) https://doi.org/10.1117/12.2649513

KEYWORDS: Microscopy, Liquid crystals, Video, Spatial resolution, Microscopes, Visualization, Prototyping, Electrodes, Dynamical systems, Chromium

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Proceedings Article | 3 October 2022 Presentation

Direct observation of the dynamic heterogeneity in soft matter by fluctuation microscope (Conference Presentation)

Jun Yamamoto

Proceedings Volume PC12207, PC1220701 (2022) https://doi.org/10.1117/12.2632880

KEYWORDS: Microscopes, Liquid crystals, Glasses, X-rays, Visualization, Structural analysis, Spatial resolution, Prototyping, Molecules, Liquids

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Proceedings Article | 1 August 2021 Presentation

Dynamics of flow-induced birefringence in phantasmagoric liquid crystals

Jun Yamamoto, Nozomu Takahashi, Giusy Scalia

Proceedings Volume 11807, 118070E (2021) https://doi.org/10.1117/12.2594463

KEYWORDS: Birefringence, Tin, Liquid crystals, Light scattering, Time metrology, Temperature metrology, Scattering, Dynamic light scattering

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Proceedings Article | 13 March 2019 Presentation

slippery interface-dynamics for the motion of the surface director (Conference Presentation)

Jun Yamamoto

Proceedings Volume 10941, 1094107 (2019) https://doi.org/10.1117/12.2508962

KEYWORDS: Interfaces, Switching, Glasses, Magnetism, Motion models, LCDs

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Proceedings Article | 18 September 2018 Presentation

Slippery interfaces: control and evaluation of the anchoring effect for the reduction of driving voltage (Conference Presentation)

Jun Yamamoto, Isa Nishiyama

Proceedings Volume 10735, 107350V (2018) https://doi.org/10.1117/12.2320278

KEYWORDS: Interfaces, Liquid crystals, LCDs, Magnetism, Polymer thin films, Polymers, Electrodes, Switching, Ultrafast phenomena, Glasses

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Proceedings Article | 14 September 2018 Presentation + Paper

Graphene: a new liquid crystal for high performance electro-optic applications

MinJae Kim, Ji Hyun Park, Sharif Shahini, Jun Yamamoto, Stephane Campidelli, Youn Sang Kim, Giusy Scalia

Proceedings Volume 10735, 107350N (2018) https://doi.org/10.1117/12.2501822

KEYWORDS: Graphene, Liquid crystals, Oxides, Electro optics, Birefringence, Polarizers, Switching, Electrodes, Magnesium, Glasses

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Proceedings Article | 19 September 2017 Open Access

Nano slippery interfaces in nematic gels -localization and lubrication of director motions (Conference Presentation)

Jun Yamamoto, Isa Nishiyama

Proceedings Volume 10361, 103610B (2017) https://doi.org/10.1117/12.2273254

KEYWORDS: Interfaces, Ultraviolet radiation, Electro optics, Fast packet switching, Dynamic light scattering, Nanostructures, LCDs

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We designed the fast switching & low driving voltage principle with nano slippery interfaces in nematic gels. Confinement effect by the gel network can accelerate the response time of nematic due the localization of director motion as similar way to the cholesteric blue phase. However, the anchoring of the director on the gel network induces the driving voltage. Slippery effect on the nano interface of the gel network can reduce the driving voltage due to the lubrication of the director motion. Since azo dye acrylates are co-polymerized with nematic gels (Azo-NGel), we can demonstrate the UV-switchable nano-slippery interface on the nematic gels. Dynamic Light Scattering (DLS) provides us the information of the dynamics of director rotation. Dispersion relation of the pure 7CB-T15 mixture completely satisfies the prediction of hydrodynamic modes in the nematic. On the contrary, the relaxation frequency of the Azo-NGel keeps fast response in the low wave-number region due to the confinement effect. Electro-Optic response (EO) of the Azo-Ngel without UV illumination shows the serious increase of the driving voltage compared to the pure 7CB-T15 mixture. When the Azo-Ngel is illuminated by UV-light Slippery interfaces can be created by the trans-cis isomerization of the Azo dye of the side-chain on the nano network of nematic gels. EO under UV illumination shows the drastic reduction of the driving voltage keeping the fast response time. We have also confirmed that the dispersion relation of the UV illuminated Azo-Ngel is almost the same as that of Azo-Ngel without UV illumination by the DLS measurement. Thus, the confinement effect for the nematic gels is still effective after the slippery interface is created by the UV illumination. We success to demonstrates that the acceleration of the response time is compatible with reduction of the driving voltage by the localization and lubrication of director motions due to the design of the nano-slippery interfaces in the nematic gels.

Proceedings Article | 21 April 2017 Presentation

Slippery interfaces: lubrication of director and helix rotation motions (Conference Presentation)

Jun Yamamoto, Waki Sakatsuji, Isa Nishiyama

Proceedings Volume 10125, 101250D (2017) https://doi.org/10.1117/12.2251313

KEYWORDS: Interfaces, Liquid crystals, Polymers, Polymer thin films, LCDs, Molecules, Fast packet switching, Liquids, Glasses, Ultraviolet radiation

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Proceedings Article | 23 March 2016 Paper

Solvent effect on columnar formation in solar-cell geometry

J. H. Park, L. Sosa-Vargas, Y. Takanishi, K. H. Kim, Y. S. Kim, Y. W. Park, J. Yamamoto, M. Labardi, J. P. Lagerwall, Y. Shimizu, G. Scalia

Proceedings Volume 9769, 97690T (2016) https://doi.org/10.1117/12.2216354

KEYWORDS: Molecular self-assembly, Molecules, Molecular assembly, Liquid crystals, Atomic force microscopy, Nanolithography, Nanostructuring, Optoelectronic devices, Solar cells, Optoelectronics, Nanowires, Crystals, Glasses, Optical microscopy, Optical alignment, Organic light emitting diodes

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Proceedings Article | 5 October 2015 Open Access

Study of liquid crystal formation of graphene oxide flakes (Withdrawal Notice)

Ji Hyun Park, Min Jae Kim, HyeRan Jo, Kieup Lee, YoungBeom Jo, Stephane Campidelli, Jun Yamamoto, Youn Sang Kim, Giusy Scalia

Proceedings Volume 9565, 956515 (2015) https://doi.org/10.1117/12.2188050

KEYWORDS: Liquid crystals, Graphene, Oxides, Current controlled current source

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Proceedings Article | 20 August 2015 Paper

Self-assembling of molecular nanowires for enhancing the conducting properties of discotic liquid crystals

Ji Hyun Park, Kyung Ho Kim, Yoichi Takanishi, Jun Yamamoto, Yung Woo Park, Youn Sang Kim, Giusy Scalia

Proceedings Volume 9558, 95580R (2015) https://doi.org/10.1117/12.2188078

KEYWORDS: Liquid crystals, Electrodes, Molecular self-assembly, Thin films, Iodine, Molecules, Doping, Atomic force microscopy, Organic materials, Nanowires

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Proceedings Article | 11 March 2015 Paper

Dynamic and complex optical patterns from colloids of cholesteric liquid crystal droplets

JungHyun Noh, Irena Drevensek-Olenik, Jun Yamamoto, Jan Lagerwall

Proceedings Volume 9384, 93840T (2015) https://doi.org/10.1117/12.2180516

KEYWORDS: Liquid crystals, Spherical lenses, Crystals, Capillaries, Photonic crystals, Spectrophotometry, Visible radiation, Optical properties, Data centers, Physics

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Proceedings Article | 19 February 2014 Paper

Effects of carbon nanotubes on a very low surfactant concentration lyotropic liquid crystal host

Hye Ran Jo, Jun Yamamoto, Jan Lagerwall, Giusy Scalia

Proceedings Volume 9004, 90040V (2014) https://doi.org/10.1117/12.2049189

KEYWORDS: Liquid crystals, Carbon nanotubes, Composites, Molecules, Polarizers, Birefringence, Nanoparticles, Capillaries, Optical microscopy, Crystals

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Proceedings Article | 8 February 2012 Paper

Pre-organized liquid crystals: biaxial nature of laterally-connected dimer

Isa Nishiyama, Yuka Tabe, Jun Yamamoto, Yoichi Takanishi, Yoko Ishii, Hiroshi Yokoyama

Proceedings Volume 8279, 827903 (2012) https://doi.org/10.1117/12.913573

KEYWORDS: Liquid crystals, Molecules, Birefringence, Molecular interactions, Physics, Active optics, Glasses, Thin films, Digital image correlation, Applied physics

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