碳纳米管悬浮液的光限幅特性实验研究

Experiment on optical limiting properties of multi-walled carbon nanotubes in water-surfactant suspensions

通过超声波降解法制备了多壁碳纳米管的水-表面活性剂悬浮液,测量了其对于1 064 nm,脉宽10 ns Nd:YAG调Q脉冲激光的光限幅曲线。实验发现:入射激光能量密度较低时,出射能量密度随入射能量密度的增加而线性增加;当入射能量密度为160 mJ/cm2时,出射能量不再线性增加并且逐渐趋近于光限幅器的嵌位输出值,约16 mJ,同时,对激光的透过率从71%下降到15%。通过Z扫描和探针光实验以及45°散射角下散射能量、散射率随入射激光能量变化曲线的测量,对碳纳米管悬浮液的光限幅机理进行了研究。结果表明:其限幅机理可能源于碳纳米管吸收激光能量后升华产生的膨胀的碳气泡对入射激光产生的非线性散射;另外,非线性折射对光限幅效果也有一定的作用。

Multi-walled carbon nanotuhes water-surfactant suspensions were prepared by ultrasonication, and the optical limiting curves were measured for 1 064 nm, 10 ns Nd： YAG Q-switched puled laser. The experimental results indicated that the output energy varied linearly with input fluences at a lower level, when the incident fluences increase to about 160 mJ/cm^2 , the output was clamped and tended to the value 16 mJ finally, and the transmittance of the sample decreased from 71% to 15%. In addition, the optical limiting mechanisms were investigated through performing Z-scan, pump-probe and 45° scattering experiments. The results show that the nonlinear scattering dominates the transmittance losses and the nonlinear refraction is secondary.