Dynamic Characterization and Impulse Response Modeling of Amplitude and Phase Response of Silicon Nanowires

Abstract

Amplitude and phase dynamics of silicon nanowires were measured using time-resolved spectroscopy. Time shifts of the maximum phase change and minimum amplitude as a function of pump power due to saturation of the free-carrier density were observed. A phenomenological impulse response model used to fit the experimental data indicated that the free-carrier lifetime was between 7.5 ≤ τfc ≤ 16.2 ns, and the two-photon absorption coefficient and the Kerr coefficient were 3 × 10-12 m.W-1 and 4 ×10-18 m-18.W-1, respectively, for silicon nanowires with lengths varying from 3.6 to 14.9 mm.

Keywords

• Silicon nanowire
• pump–probe spectroscopy
• two-photon absorption (TPA)
• free-carrier absorption (FCA)