Kiyotaka Miura

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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 anisotropic bubble formation at the boundary of an irradiated region and modification transition from microscopic bubbles formation to self-assembled form birefringence(More)
The femtosecond laser induced micro- and nanostructures for the application to the three-dimensional optical data storage are investigated. We have observed the increase of refractive index due to local densification and atomic defect generation, and demonstrated the real time observation of photothermal effect after the femtosecond laser irradiation inside(More)
Direct three-dimensional laser writing of amorphous waveguides inside glass has been studied intensely as an attractive route for fabricating photonic integrated circuits. However, achieving essential nonlinear-optic functionality in such devices will also require the ability to create high-quality single-crystal waveguides. Femtosecond laser irradiation is(More)
Construction of an active composite with multicolor visible and broadband near-infrared luminescence is of great technological importance for various applications, including three-dimensional (3D) display, broadband telecommunication, and tunable lasers. The major challenge is the effective management of energy transfer between different dopants in(More)
Ultrashort pulse lasers have allowed probing of molecular dynamics in real time on the femtosecond time scale, [ 1 ] with exotic behavior ranging from alignment of molecules and clusters, [ 2 , 3 ] structural deformation, [ 4 ] phase transitions on solid, [ 5 ] and electron localization in magnetic materials. [ 6 ] A recent progress in high power ultrashort(More)
Laser-fabrication of complex, highly oriented three-dimensional ferroelectric single crystal architecture with straight lines and bends is demonstrated in lanthanum borogermanate model glass using a high repetition rate femtosecond laser. Scanning micro-Raman microscopy shows that the c-axis of the ferroelectric crystal is aligned with the writing direction(More)
We present the first experimental evidence of anisotropic photosensitivity of an isotropic homogeneous medium under uniform illumination. Our experiments reveal fundamentally new type of light induced anisotropy originated from the hidden asymmetry of pulsed light beam with a finite tilt of intensity front. We anticipate that the observed phenomenon, which(More)
1Advanced Materials Science Research and Development Center, Kanazawa Institute of Technology, 3-1 Yatsukaho, Hakusan, Ishikawa 924-0838, Japan 2Oarai Research Center, Chiyoda Technol Corpration, 3681 Narita-cho, Oarai-machi Higashi-ibaraki-gun, Ibaraki 311-1313, Japan 3Nagase Landauer, C22 gaiku-1, Suwa, Tsukuba, Ibaraki 300-2686, Japan 4Graduated School(More)
Diamond is a promising platform for sensing and quantum processing owing to the remarkable properties of the nitrogen-vacancy (NV) impurity. The electrons of the NV center, largely localized at the vacancy site, combine to form a spin triplet, which can be polarized with 532 nm laser light, even at room temperature. The NV's states are isolated from(More)
Carbon nanoparticles (CNPs), hollow CNPs, nanodiamonds, and hybrid graphene spheres (HGSPs) are produced by using fs laser ablation in solution. These carbon nanostructures emit tunable photoluminescence and two-photon luminescence. The photoinduced layer-by-layer assembly of graphene nanosheets is observed to form HGSPs with tailored broadly-ranged sizes(More)