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  1. No Access

    Article

    High-intensity near-field generation for silicon nanoparticle arrays with oblique irradiation for large-area high-throughput nanopatterning

    We present near-field distributions around an isolated 800-nm silica or silicon nanoparticle, and nanoparticle arrays of 800-nm silica or silicon nanoparticles, on a silicon substrate by the finite-difference ...

    T. Miyanishi, Y. Tsunoi, M. Terakawa, M. Obara in Applied Physics B (2012)

  2. No Access

    Article

    Order to disorder optical phase transition in random photonic crystals

    Transition process of optical modal properties induced by the introduction of randomness into random photonic crystals is investigated by a computational method. We analyze an impulse response of two-dimension...

    S. Takeda, S. Hamada, R. Peretti, P. Viktorovitch, M. Obara in Applied Physics B (2012)

  3. No Access

    Article

    Tuneabilities of localized electromagnetic modes in random nanostructures for random lasing

    The modal characteristics of localized electromagnetic waves inside random nanostructures are theoretically presented. It is crucial to know the tuneabilities of the localized modes systematically for demonstr...

    S. Takeda, M. Obara in Applied Physics B (2010)

  4. No Access

    Article

    Femtosecond-laser nanofabrication onto silicon surface with near-field localization generated by plasmon polaritons in gold nanoparticles with oblique irradiation

    Nanohole fabrication process with gold nanoparticles irradiated by femtosecond laser at different incident angles is investigated. Nanoparticles with diameter of 200 nm and laser irradiation with center wavele...

    T. Miyanishi, T. Sakai, N. N. Nedyalkov, M. Obara in Applied Physics A (2009)

  5. No Access

    Article

    Extremely selective modal oscillation of random lasing induced by strong multiple scattering

    We report on a new physical aspect of random lasing, an extremely selective modal oscillation by using a two-dimensional calculation model. The developed model consists of two theoretical subsystems, two-dimen...

    S. Takeda, M. Obara in Applied Physics B (2009)

  6. No Access

    Article

    Development of a highly stable Yb:YAG thin disk pulsed green laser for high power Ti:sapphire based amplifier at 100 kHz repetition rate

    We have developed a pulsed Yb:YAG thin disk green laser for pum** a 100 kHz and 10 W femtosecond laser. We optimized numerically and experimentally the open duration of the acousto-optic (AO) Q-switcher and ...

    T. Imahoko, K. Takasago, M. Kamata, J. Sakuma, T. Sumiyoshi, H. Sekita… in Applied Physics B (2007)

  7. No Access

    Article

    Tunable mid-infrared, high-energy femtosecond laser source for glyco-protein structure analysis

    We have developed a 6–12 μm mid-infrared (MIR) femtosecond laser source for glyco-protein structure analysis. The MIR femtosecond laser pulses are generated by a differential frequency generation (DFG) configu...

    T. Imahoko, K. Takasago, T. Sumiyoshi, H. Sekita, K. Takahashi… in Applied Physics B (2007)

  8. No Access

    Article

    Nanostructuring of silicon surface by femtosecond laser pulse mediated with enhanced near-field of gold nanoparticles

    Nanostructure fabrication on a silicon substrate using a near-field electromagnetic enhancement in the vicinity of gold nanoparticles is studied. Experimental and theoretical investigations are made in order t...

    N.N. Nedyalkov, H. Takada, M. Obara in Applied Physics A (2006)

  9. No Access

    Article

    Improvement of surface smoothness of Nd:KGd(WO4)2 films by nozzle-gas-assisted pulsed-laser deposition

    We have demonstrated efficient film oxidation of Nd:KGW [or Nd:KGd(WO4)2] films using a newly developed nozzle-gas-assisted pulsed-laser deposition (NGA-PLD) method. This technique is systematically studied and e...

    T. Okato, M. Obara in Applied Physics A (2005)

  10. No Access

    Article

    Materials processing by use of a Ti:Sapphire laser with automatically-adjustable pulse duration

    We have developed an automatic pulsewidth-adjustable femtosecond Ti:Sapphire laser system that can generate an output of 50 fs-1 ps in duration, and sub-mJ/pulse at a repetition rate of 1 kpps. The automatic p...

    M. Kamata, T. Imahoko, K. Ozono, M. Obara in Applied Physics A (2004)

  11. No Access

    Article

    Control of the refractive index change in fused silica glasses induced by a loosely focused femtosecond laser

    We demonstrate waveguide fabrication using of a loosely focused femtosecond laser that induces both nonlinear ionization and nonlinear propagation in silica glasses without any scanning process. The numerical ...

    M. Kamata, M. Obara in Applied Physics A (2004)

  12. No Access

    Article

    Fabrication of Nd:KGW film on a Si substrate with a CeO2 buffer layer

    Highly textured single-oriented (110) Nd-doped potassium gadolinium tungstate [Nd:KGd(WO4)2 or Nd:KGW] thin films were successfully fabricated on (100) Si substrate by introducing a (100) CeO2 buffer layer using ...

    T. Okato, P.A. Atanasov, R.I. Tomov, M. Obara in Applied Physics A (2003)

  13. No Access

    Article

    Pulsed-laser deposition of a Nd:KGd(WO4)2 waveguide in Ar and O2 environments

    Thin-film Nd-doped potassium gadolinium tungstate (Nd:KGW or KGd(WO4)2) waveguides are deposited on (1102)sapphire or (100)YAG substrates by KrF laser ablation of potassium-rich ceramic targets in Ar and O2. The ...

    T. Okato, P.A. Atanasov, M. Obara in Applied Physics A (2003)

  14. No Access

    Article

    Tailored ablation processing of advanced biomedical hydroxyapatite by femtosecond laser pulses

    The micromachining of hydroxyapatite (HAp) is highly important for orthopedics and dentistry, since human bone and teeth consist mainly of HAp. We demonstrate ultrashort Ti:sapphire laser ablation of HAp, usin...

    K. Ozono, M. Obara in Applied Physics A (2003)

  15. No Access

    Article

    Combination of high-intensity femtosecond laser pulses for generation of time-dependent polarization pulses and ionization of atomic gas

    Time-dependent polarization pulses are generated by combining two perpendicularly polarized, high-intensity laser pulses. The time evolution of the polarization state of the combined laser pulse is measured by...

    M. Kakehata, R. Ueda, H. Takada, K. Torizuka, M. Obara in Applied Physics B (2000)

  16. No Access

    Article

    Ablation characteristics of Au, Ag, and Cu metals using a femtosecond Ti:sapphire laser

    Femtosecond laser ablation of metallic bulk crystals of Au, Ag and Cu was experimentally studied with laser pulse widths ranging from 120 fs through 800 fs at a center wavelength of 780 nm for micro-machining...

    K. Furusawa, K. Takahashi, H. Kumagai, K. Midorikawa, M. Obara in Applied Physics A (1999)

  17. No Access

    Article

    Phase-matched third-harmonic generation by nonlinear phase shift in a hollow fiber

     W/cm2 are introduced into a 1.8-cm hollow fiber in room air. From the observation of the third-harmonic beam quality and spectra, it is clarified that the harmonics are pumped at the leading edge of the fundamen...

    Y. Tamaki, K. Midorikawa, M. Obara in Applied Physics B (1998)

  18. No Access

    Article

    Wavelength-stable, narrow-spectral-width oscillation of an AlGaInP diode laser coupled to a BaTiO3:Co stimulated photorefractive backscattering phase conjugator

    ) stimulated photorefractive backscattering (SPBS) phase conjugator. The SPBS process was successfully achieved by the combination of the short-wavelength diode laser and the highly doped photorefractive BaTiO3:C...

    A. Shiratori, M. Obara in Applied Physics B (1997)

  19. No Access

    Article

    Efficient ablation of organic polymers polyether sulphone and polyether ether ketone by a TEA CO2 laser with high perforation ability

    Organic polymer (PES: PolyEther Sulphone and PEEK: PolyEther Ether Ketone) ablation with oscillation-line selected TEA CO2 lasers is successfully demonstrated. With different irradiation conditions the ablative e...

    T. Sumiyoshi, Y. Ninomiya, H. Ogasawara, M. Obara, H. Tanaka in Applied Physics A (1994)