三束延时飞秒激光在4H-SiC表面调控制备亚波长纳米结构  

Controllable Fabrication of Sub-Wavelength Nanostructures on 4H-SiC Surface Using Delayed Triple Femtosecond

作　　者：和万霖 秦彦军 He Wanlin;Qin Yanjun(School of Science,Xi’an Shiyou University,Xi’an 710065,Shaanxi,China;School of Science,Xinjiang Institute of Technology,Aksu 843100,Xinjiang,China)

机构地区：[1]西安石油大学理学院,陕西西安710065 [2]新疆理工学院理学院,新疆阿克苏843100

出　　处：《光学学报》2025年第1期169-176,共8页Acta Optica Sinica

基　　金：国家自然科学基金(11847138);陕西省自然科学基础研究计划(2019JQ-813);新疆维吾尔自治区高校基本科研业务费科研项目(XJEDU2024P091)。

摘　　要：亚波长尺度纳米结构的飞秒激光制备是现代光子学的前沿研究领域之一,在多个领域具有广泛的应用前景。利用三束飞秒激光直写加工技术,对4H-SiC材料表面亚波长周期结构特性及产生机理进行研究。通过控制三束入射激光偏振方向和延迟时间,在样品表面诱导产生了不同尺度和不同维度的亚波长纳米结构。实验结果表明:通过调节入射激光脉冲数目和延迟时间,可以实现诱导的纳米结构空间周期由高空间频率向低空间频率转变。同时,通过控制三束入射激光之间的偏振方向,在样品表面诱导产生二维低空间频率纳米方块结构和菱形结构。理论分析认为:在激光辐照材料表面的过程中,瞬态温度光栅(或瞬态折射率光栅)扮演着重要角色,瞬态温度光栅的演化及其后续能量弛豫过程最终重塑了永久性的纳米结构;同时,激光辐照样品引起的粗糙度,则进一步促进瞬态温度光栅的激发和永久性纳米结构的形成。研究结果对激光诱导表面周期结构的可控制备及形成机理研究具有重要意义。Objective The fabrication of subwavelength nanostructures induced by femtosecond laser irradiation is critical to modern nanophotonics and has extensive applications across various fields.This study investigates the subwavelength periodic structural characteristics and formation mechanism of 4H-Si C material surfaces induced by delayed triple femtosecond laser pulses.By controlling the polarization direction and delay time of the three incident laser beams,subwavelength nanostructures of varying scales and dimensions are produced on the sample surface.Experimental results indicate that by adjusting the number of laser pulses and the delay time,the spatial period of the induced nanostructures can shift from high spatial frequency to low spatial frequency.In addition,by modulating the polarization direction between the three laser beams,two-dimensional low-spatial-frequency nano-square and nano-rhombic structures are generated on the sample surface.To explain the physical mechanism behind the formation of these subwavelength nanostructures,a transient temperature grating model is proposed.This model suggests that transient temperature gratings (or transient refractive index gratings) play a pivotal role in the laser irradiation process.The evolution of these gratings and subsequent energy relaxation ultimately result in permanent nanostructures.The surface roughness caused by laser irradiation further enhances the excitation of transient temperature gratings,promoting the formation of these permanent nanostructures.This research provides valuable insights into the controllable fabrication and underlying mechanisms of laser-induced periodic surface structures (LIPSSs).Methods In this study,we use a Ti:sapphire femtosecond laser amplifier (Spectra-Physics HP-Spitfire) as the irradiation source,delivering horizontally polarized pulse trains at a 1 k Hz repetition rate,with a central wavelength of 800 nm and a pulse duration of 50 fs.The maximum pulse energy delivered by the system is 2 m J.The laser output is split in

关 键 词：激光光学 飞秒激光 表面周期结构 表面等离激元 瞬态温度光栅 

分 类 号：O436[机械工程—光学工程]