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用化学气相沉积法制备了多壁碳纳米管,并将其溶解在甲苯溶液中.用波长为1064nm的皮秒脉冲激光测量该样品的透过率,发现了非常明显的光限幅特性.当入射光强较小时,透射光强度随入射光强度的增大而增大,输出与输入为线性关系;随着入射光强的增大,透射光强增长的速度明显变慢,并逐渐趋于饱和.当入射光强度较小时,样品的透过率接近100%;而当入射光强为8GW/cm2时,非线性透过率达到30%.根据三光子吸收理论计算,理论拟合与实验结果非常符合,说明多壁碳纳米管的三光子吸收产生了光限幅效应.实验测得三光子吸收系数为γ=1.36×10-20cm3/W2,相应的三光子吸收截面为σ′3=2.8×10-77cm6.s2.
Multi-walled carbon nanotubes were prepared by chemical vapor deposition and dissolved in toluene solution.The transmissivity of the sample was measured by picosecond pulsed laser with a wavelength of 1064nm and the very obvious optical limiting properties were found. When the incident light intensity is small, the intensity of transmitted light increases with the increase of incident light intensity, and the output and input are in a linear relationship. With the increase of incident light intensity, the transmitted light intensity increases obviously slower and tends to gradually Saturation. When the incident light intensity is small, the transmittance of the sample is close to 100%, while when the incident light intensity is 8GW / cm2, the nonlinear transmittance reaches 30%. According to the theory of three-photon absorption, theoretical fitting and experiment The results are in good agreement, indicating that the three-photon absorption of multi-walled carbon nanotubes produced optical limiting effect.Experimentally measured three-photon absorption coefficient of γ = 1.36 × 10-20cm3 / W2, the corresponding three-photon absorption cross-section σ’3 = 2.8 × 10-77cm6.s2.