反射z扫描方法测量碲化铋晶体的非线性折射率

Measurement of nonlinear refractive index of bulk bismuth telluride based on reflection z-scan

为了研究3维拓扑绝缘体碲化铋(Bi_2Te_3)的非线性光学特性,采用反射z扫描方法,实验测量了800nm飞秒脉冲激光的非线性折射系数。通过理论计算与实验数据拟合获得碲化铋晶体的非线性折射率达到10-14m2/W数量级,为石英的105倍;随着入射功率的增大,其非线性折射率逐渐减小,在峰值光强达到85GW/cm^2后趋于常数不变。结果表明,碲化铋是一种高非线性光学材料,有望应用于全光信号处理、光开关等方面。

In order to study nonlinear refractive index of bismuth telluride , a 3-D topological insulator , nonlinear refractive index of 800 nm femtosecond pulse laser was measured by reflection z-scan method .After theoretical calculation and experimental data fitting, nonlinear refractive index of bismuth telluride crystal could reach the order of magnitude of 10 -14 m2/W, 105 times of that of quartz.Nonlinear refractive index decreased with the increase of incident power .Until peak intensity reached 85GW/cm2, nonlinear refractive index tended to be a constant .The results show that bismuth telluride is a remarkable nonlinear optical material which has huge potential in the application of all-optical signal processing and optical switching .