Extended-area nanostructuring of TiO2 with femtosecond laser pulses at 400 nm using a line focus
Extended-area nanostructuring of TiO2 with femtosecond laser pulses at 400 nm using a line focus
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DOI：
10.1088/0957-4484/21/15/155302
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发表时间：
2010-04-16
期刊：
影响因子：
3.5
通讯作者：
Grunwald, Ruediger
中科院分区：
文献类型：
--
作者：
Das, Susanta Kumar;Dasari, Kiran;Grunwald, Ruediger
报道了一种利用波长约为400 nm的频率转换飞秒激光脉冲在金红石型TiO2中制备纳米级激光诱导周期性表面结构（LIPSS）的有效方法。利用柱面透镜的线聚焦，在固定和移动的衬底上获得扩展区域结构。在限定的条件下，相对于脉冲数，脉冲能量和扫描速度，两种类型的波纹状LIPSS与高和低的空间频率（HSFL，LSFL）的周期在90 nm和340 nm的范围内，分别形成。特别地，较低数量的高能脉冲有利于LSFL的产生，而较高数量的低能脉冲使得能够优先产生HSFL。Drude模型的基础上的理论计算支持的假设，折射率的变化，光激发载流子是一个主要的机制负责LSFL。此外，随机子结构的外观小至30纳米叠加低空间频率波纹的演示和讨论其可能的起源。
An efficient way to generate nanoscale laser-induced periodic surface structures (LIPSS) in rutile-type TiO2 with frequency-converted femtosecond laser pulses at wavelengths around 400 nm is reported. Extended-area structuring on fixed and moving substrates was obtained by exploiting the line focus of a cylindrical lens. Under defined conditions with respect to pulse number, pulse energy and scanning velocity, two types of ripple-like LIPSS with high and low spatial frequencies (HSFL, LSFL) with periods in the range of 90 nm and 340 nm, respectively, were formed. In particular, lower numbers of high energetic pulses favour the generation of LSFL whereas higher numbers of lower energetic pulses enable the preferential creation of HSFL. Theoretical calculations on the basis of the Drude model support the assumption that refractive index changes by photo-excited carriers are a major mechanism responsible for LSFL. Furthermore, the appearance of random substructures as small as 30 nm superimposing low spatial frequency ripples is demonstrated and their possible origin is discussed.