飞秒激光双光子加工的极限分辨力

Investigation into ultimate resolution by femtosecond laser two-photon fabrication technique

采用3维压电微移动台高速扫描方式控制曝光时间与高精密转台精确控制圆形渐变衰减片以控制曝光功率两种方法,曝光时间和曝光功率可分别精确控制至0.02 ms和7 pW。通过精确控制聚合阈值附近处的曝光时间和曝光功率,分别在玻璃基板上获得了35 nm和45 nm的聚合物纳米线条,分别为所使用激光波长的1/22和1/17。实验结果表明,当曝光时间或曝光功率在加工阈值附近时,曝光时间和功率的微量减少会使聚合线宽急剧下降。

One 3-dimensional piezostage and one rotation stage are used in two-photon fabrication systems for controlling expose time and expose power with precision as high as 0.02 ms and 7 pW respectively.By accurate controlling expose time and laser power near polymerization threshold,35 nm and 45 nm polymer line on cover glass are obtained respectively,which is only 1/22 and 1/17 of the laser wavelength used for fabrication.These results are the highest linewidth resolution obtained by two photon fabrication on cover glass until now.It is revealed that linewidth resolution can be improved efficiently with ultra-small reduction of the expose time or expose power near polymerization threshold.The further possible improvement for resolution of two-photon process was analyzed in the paper.