Kazuyuki Hirao

Temperature distribution and modification mechanism inside glass with heat accumulation during 250 kHz irradiation of femtosecond laser pulses (2008)

Sakakura, Masaaki, Shimizu, Masahiro, Shimotsuma, Yasuhiko, Miura, Kiyotaka, Hirao, Kazuyuki

Heat accumulation by high repetition rate femtosecond laser irradiation inside glass generates a much larger modification than that by a single pulse. In this study, we determined the temperature...

Ultrashort-pulse laser calligraphy (2008)

Yang, Weijia, Kazansky, Peter G., Shimotsuma, Yasuhiko, Sakakura, Masaaki, Miura, Kiyotaka, Hirao, Kazuyuki

Control of structural modifications inside silica glass by changing the front tilt of an ultrashort pulse is demonstrated, achieving a calligraphic style of laser writing. The phenomena of...

Ultrashort-pulse laser calligraphy (2008)

Yang, Weijia, Kazansky, Peter G., Shimotsuma, Yasuhiko, Sakakura, Masaaki, Miura, Kiyotaka, Hirao, Kazuyuki

Control of structural modifications inside silica glass by changing the front tilt of an ultrashort pulse is demonstrated, achieving a calligraphic style of laser writing. The phenomena of...

Scattering-based hole burning through volume speckles in a random medium with tunable diffusion constant (2008)

Murai, Shunsuke, Fujita, Koji, Hirao, Takayuki, Nakanishi, Kazuki, Hirao, Kazuyuki, Tanaka, Katsuhisa

A photoreactive random medium with tunable diffusion constant D is fabricated by infiltrating Sm2+-doped macroporous aluminosilicate glass with liquid crystal (LC). Time-resolved transmission...

Photoinduced microchannels inside silicon by femtosecond pulses (2008)

Chen, Tao, Si, Jinhai, Hou, Xun, Kanehira, Shingo, Miura, Kiyotaka, Hirao, Kazuyuki

We reported on the fabrication of microchannels in the interior of silicon wafers using a femtosecond laser of 800 nm wavelength, which was in the absorption region of silicon. The scanning electron...

Ion exchange in glass using femtosecond laser irradiation (2008)

Kanehira, Shingo, Miura, Kiyotaka, Hirao, Kazuyuki

We explain the occurrence of ion exchange and an index profile around the focal point inside a commercial crown glass formed by femtosecond laser irradiation. The index profile in the photoinduced...

Femtosecond pulsed laser as a microscalpel for microdissection and isolation of specific sections from biological samples (2007)

Sakakura, Masaaki, Kajiyama, Shinichiro, Tsutsumi, Masafumi, Si, Jinhai, Fukusaki, Eiichiro, Tamaru, Yutaka, ...

The fermosecond laser is a candidate tool for dissecting and obtaining specific tissues or cells from biological samples. In this paper, we report on the dissection of flammable (heat-sensitive)...

Photoconversion of copper flakes to nanowires with ultrashort pulse laser irradiation (2007)

Shimotsuma, Yasuhiko, Yuasa, Toshirou, Homma, Hidekazu, Sakakura, Masaaki, Nakao, Atsuo, Miura, Kiyotaka, ...

The size and shape of nanoscale materials provide important control over many of the physics and chemical properties, including electric and thermal conductivity, luminescence, and catalytic...

Three-dimensional micro- and nano-fabrication in transparent materials by femtosecond laser (2005)

Shimotsuma, Yasuhiko, Hirao, Kazuyuki, Kazansky, Peter G., Qiu, Jiarong

Femtosecond pulsed lasers have been widely used for materials microprocessing. Due to their ultrashort pulse width and ultrahigh light intensity, the process is generally characterized by the...

Three-dimensional micro- and nano-fabrication in transparent materials by femtosecond laser (2005)

Shimotsuma, Yasuhiko, Hirao, Kazuyuki, Kazansky, Peter G., Qiu, Jiarong

Femtosecond pulsed lasers have been widely used for materials microprocessing. Due to their ultrashort pulse width and ultrahigh light intensity, the process is generally characterized by the...

Nano-modification inside transparent materials by femtosecond laser single beam (2005)

Shimotsuma, Yasuhiko, Hirao, Kazuyuki, Qiu, Jiarong, Kazansky, Peter G.

Periodic nanostructures along the polarization direction of light are observed inside silica glasses and tellurium dioxide single crystal after irradiation by a focused single femtosecond laser beam....

3D self-organized periodic nano-structures in glass irradiated by ultrashort light pulses (2005)

Kazansky, Peter G., Bricchi, Erica, Shimotsuma, Yasuhiko, Qui, Jiangrong, Hirao, Kazuyuki

Three-dimensional periodic nano-structures structures are observed in silica glass irradiated by intense femtosecond laser pulses. The structures could present the first evidence of nano-vortex...

Femtosecond laser micro-machining and self-organized nano-structures in glass (2003)

Kazansky, Peter G., Qiu, Jiarong, Shimotsuma, Yasuhiko, Hirao, Kazuyuki

New phenomena of anisotropic light scattering, anisotropic Cherenkov third-harmonic generation, photoinduced birefringence and anisotropic reflection from femtosecond direct-write structures are...

Optical Nonlinearity of Sputtered Co3O4-SiO2-TiO2 Thin Films (2002)

Yamamoto, Hiroki, Naito, Takashi, Hirao, Kazuyuki

Optical non-linearity of cobalt oxide with SiO2-TiO2 additives was investigated, and the change mechanism of the refractive index (n) and extinction coefficient (k), based on the relation between...

Physical Properties and Structure of Silica-Alumina-Europium Oxide Glasses. (1998)

Tanabe, Setsuhisa, Soga, Naohiro, Hirao, Kazuyuki, Hanada, Teiichi

SiO2-Al2O3-Eu2O3 glasses were prepared for the composition 50 SiO2-(50-x)Al2O3-(x)Eu2O3, and their density, sound velocity, and elastic modulus were measured. The chemical shift of the Al-K-alpha...

Elastic Properties and Molar Volume of Rare-Earth Aluminosilicate Glasses. (1998)

Tanabe, Setsuhisa, Hirao, Kazuyuki, Soga, Naohiro

The elastic properties, molar volume, and glass transition temperature (T(sub g)) of rare-earth-containing aluminosilicate glasses were investigated in the compositions of SiO2-LnAlO3 and...

Preparation and Optical Properties of Transparent Glass-Ceramics Containing Cobalt(II) Ions. (1998)

Tanaka, Katsuhisa, Mukai, Takashi, Ishihara, Tsuguo, Hirao, Kazuyuki, Soga, Naohiro

Transparent glass-ceramics containing ZnAl2O4:Co(2+) and LiGa5O8:Co(2+) crystallites have been prepared by heat treatment of glasses in the zinc aluminosilicate and lithium gallate silicate systems,...