Ultrafast nonlinear effects in hydrogenated amorphous silicon wire waveguide
Ultrafast nonlinear effects in hydrogenated amorphous silicon wire waveguide
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DOI：
10.1364/oe.18.005668
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发表时间：
2010-03-15
期刊：
影响因子：
3.8
通讯作者：
Mori, Masahiko
中科院分区：
文献类型：
--
作者：
Shoji, Yuya;Ogasawara, Takeshi;Mori, Masahiko
我们首次展示了使用飞秒脉冲的氢化非晶硅 (a-Si:H) 线波导的超快光学非线性响应。我们展示了使用外差泵浦探针方法测量的交叉相位和交叉吸收调制，并估计了非晶硅波导的光学克尔系数和双光子吸收系数。 0.8 eV的泵浦能量略低于在a-Si:H带隙处实现双光子激发所需的能量（类似于1.7 eV）。观察到小于 100 fs 的超快响应，这表明带隙中的局域态抑制了自由载流子效应。 (C) 2010 美国光学学会
We, for the first time, present the ultrafast optical nonlinear response of a hydrogenated amorphous silicon (a-Si:H) wire waveguide using femtosecond pulses. We show cross-phase and cross-absorption modulations measured using the heterodyne pump-probe method and estimate the optical Kerr coefficient and two-photon absorption coefficient for the amorphous silicon waveguide. The pumping energy of 0.8 eV is slightly lower than that required to achieve two-photon excitation at the band gap of a-Si:H (similar to 1.7 eV). An ultrafast response of less than 100 fs is observed, which indicates that the free-carrier effect is suppressed by the localized states in the band gap. (C) 2010 Optical Society of America