多脉冲激光对碳纳米管悬浮液光限幅特性影响

Effects of Optical Limiting Properties of Suspended Carbon Nanotubes by Multi-pulse Laser

利用实验的方法研究了碳纳米管悬浮液对脉宽8ns,波长532nm多脉冲激光的光限幅效应.分析了直径分布为10～20nm的多壁碳纳米管悬浮液对重复频率分别为1Hz、3Hz、5Hz、10Hz情况下532nm激光的光限幅效应,分析计算了不同重复频率下碳纳米管悬浮液的限幅阈值,比较了不同焦距的透镜会聚入射光束情况下对碳纳米管悬浮液光限幅效果的影响.实验结果表明:碳纳米管悬浮液对不同重复频率的532nm激光都具有较强的光限幅特性;碳纳米管悬浮液对激光在不同重复频率入射情况下的光限幅阈值变化很大,当入射激光的重复频率为5Hz时,碳纳米管悬浮液的光限幅阈值比单脉冲激光入射时的限幅阈值低了2倍,重复频率为10Hz时的限幅阈值比单脉冲时的限幅阈值低了近3倍;碳纳米管在紧焦系统中的光限幅效果更好.

Effects of repetition frequency on optical limiting properties of suspended carbon nanotubes irradiated by a 8 ns 532 nm laser was investigated in the experiment. Optical limiting properties of suspended carbon nanotubes（10-20 nm） with incident laser beam at 1 Hz,3 Hz,5 Hz,10 Hz repetition frequency were analyzed, and optical limiting effects of suspended carbon nanotubes irradiated by laser beams focused by different focal lenses were compared, and the limiting threshold of suspended carbon nantotubes at incident laser beam with different repetition frequency was quantitatively described. The experimental results indicate that suspended carbon nantobutes has good optical limiting response to 532 nm laser at different repetition frequency,and optical limiting thresholds with incident laser beam of 5 Hz and 10 Hz repetition frequency are much nearly two and three times lower than signal incident laser pulse, respectively. And the experimental results also indicate that the suspended carbon nanotubes has better optical limiting response in the tight focus system than in the general focus system.