飞秒激光诱导亚波长与深亚波长纳米周期结构的超快动力学

飞秒激光在金属、半导体、介质材料中诱导纳米周期条纹结构的机制一直是一个富有挑战性的热点课题。如何研究飞秒激光照射下电子的激发与能量周期沉积等超快动力学是突破这一难题的关键所在。激光诱导亚波长、深亚波长周期条纹在微纳光学元器件制造等方面的应用也获得了迅速发展。 本项目计划创新发展同时具有高时间分辨、高空间分辨、高灵敏度的超快成像实验系统，研究飞秒激光能量周期沉积与周期条纹形成的超快动力学。建立飞秒激光与纳米结构的耦合动力学模型，研究飞秒激光照射下电子的激发、等离子体的形成、等离子体波与激光的干涉等微观超快过程。理论和实验相结合，揭示飞秒激光诱导纳米周期结构的物理机制。发展飞秒激光纳米加工的新原理、新方法，制备刻线线宽小于50纳米的结构，探索这些结构在纳米光学元器件的应用。

Subwavelength and deep subwavelength periodic ripples have been intensely studied in metals, semiconductors, and dielectrics under the irradiation of femtosecond laser pulses. The formation mechanisms is an interesting and puzzling problem. The key point is how to study the ultrafast dynamics of electron excitation and laser energy deposition under fs laser irradiation. In this project, we will develop a bump-probe experimental system with 50 fs temporal resolution, 200 nm spatial resolution, and high sensitivity by using a 50 fs, 800 nm laser and OPA system, and study the formation dynamics of subwavelength and deep subwavelength periodic ripples in metal, semiconductor, dielectrics, and polymers, including electrons excitation and periodic distribution. The coupling model of fs laser and nanostructures will be resolved by quantum perturbation method and finite element method. Another goal is to study the fabrication of 2D and 3D nanostructures with resolution less than 50 nm, and their applications in nano-photonic elements.