レーザー研究
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
30 巻, 8 号
選択された号の論文の9件中1~9を表示しています
「超高速ファイバ非線形光学」解説小特集号
解説小特集
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レーザーオリジナル
  • 西澤 典彦, 後藤 俊夫
    2002 年 30 巻 8 号 p. 456-461
    発行日: 2002/08/15
    公開日: 2009/10/21
    ジャーナル フリー
    Characteristics of ultrashort pulse propagation in optical fibers at the wavelength region of 1.55 μm are experimentally analyzed using the cross-correlation frequency resolved optical gating (X-FROG) technique. In the anomalous dispersive fibers, widely wavelength tunable femtosecond soliton pulse is generated. The spectrogram of almost transform limited soliton pulse around 2 μm is observed. In the dispersion shifted fibers, the wavelength tunable soliton pulse and anti-stokes pulse are generated. As the results of X-FROG measurement, it is clarified that the anti-stokes pulse is overlapped with the soliton pulse and trapped by the soliton pulse. In the highly nonlinear optical fibers, 1.2-2.1 μm ultra-widely broadened super continuum and 1.46-1.68 μm linearly chirped one are generated. The spectrograms of generated super continuum are observed. The phenomenon of pulse trapping is also observed in generated super continuum.
  • 藤平 好彦, 欠端 雅之, 高田 英行, 小林 洋平, 鳥塚 健二, 本間 哲哉, 高橋 英郎
    2002 年 30 巻 8 号 p. 462-467
    発行日: 2002/08/15
    公開日: 2009/10/21
    ジャーナル フリー
    We demonstrated measurement of carrier-envelope phase (CEP) changes of amplified laser pulses by utilizing spectral interferometry between the white-light continuum and its second harmonic. The white-light continuum was generated by self-phase modulation (SPM) in a gas-filled hollow fiber. This method enables us to measure the CEP changes of low-repetition rate laser pulses on a shot-to-shot basis. The CEP-change of the amplified laser pulses exhibits random distribution that is mainly due to the CEP change fluctuation of the seed pulses from a carrier-envelope-offset (CEO) uncontrolled oscillator. We also demonstrated the CEO measurement of a mode-locked Ti:Sapphire oscillator. We utilized the self-referencing method, which measures the temporal beat frequency between the white-light continuum and its second harmonic. The white-light continuum was generated by the SPM in a micro-structure fiber. The temporal evolution of the beat signal showed CEO fluctuation of the uncontrolled oscillator.
一般論文
レーザーオリジナル
  • 谷山 哲哉
    2002 年 30 巻 8 号 p. 468-471
    発行日: 2002/08/15
    公開日: 2009/10/21
    ジャーナル フリー
    The output of a CW type CO2 laser beam is modulated into square waves and then irradiated to a metal plate. Thermo elastic wave appeared at the irradiated part and propagated into the metal plate. A PZT is mounted on the back side of the metal plate to detect thermo elastic wave. The phase angle of thermo elastic wave changes with the modulation frequency. In this paper, the modulation frequency ƒ0 has been obtained at which the phase angle becomes 0 degree. When the thickness of the metal plate is l and the thermal diffusivity λ the relation of λ = 0.769ƒ0l 2 is obtained. If l is known, λ can be obtained by measuring ƒ0. This method is believed allow as to measure λ of not only pure metals, but also alloys.
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