Carletti L, Sinobad M, Ma P, Yu Y, Allioux D, Orobtchouk R, Brun M, Ortiz S, Labeye P, Hartmann J M, Nicoletti S, Madden S, Luther-Davies B, Moss D J, Monat C, Grillet C
Opt Express. 2015 Dec 14;23(25):32202-14. doi: 10.1364/OE.23.032202.
We characterize the nonlinear optical response of low loss Si(0.6)Ge(0.4) / Si waveguides in the mid-infrared between 3.3 μm and 4 μm using femtosecond optical pulses. We estimate the three and four-photon absorption coefficients as well as the Kerr nonlinear refractive index from the experimental measurements. The effect of multiphoton absorption on the optical nonlinear Kerr response is evaluated and the nonlinear figure of merit estimated providing some guidelines for designing nonlinear optical devices in the mid-IR. Finally, we compare the impact of free-carrier absorption at mid-infrared wavelengths versus near-infrared wavelengths for these ultra-short pulses.
我们使用飞秒光脉冲表征了低损耗Si(0.6)Ge(0.4)/Si波导在3.3μm至4μm中红外波段的非线性光学响应。我们从实验测量中估算了三光子和四光子吸收系数以及克尔非线性折射率。评估了多光子吸收对光学非线性克尔响应的影响，并估算了非线性品质因数，为中红外非线性光学器件的设计提供了一些指导。最后，我们比较了这些超短脉冲在中红外波长与近红外波长下自由载流子吸收的影响。
