关键词: 飞秒激光加工/
光学衍射极限/
蓝宝石/
微纳结构
English Abstract
Sub-diffraction-limit fabrication of sapphire by femtosecond laser direct writing
Gao Si,Wang Zi-Han,
Hua Jian-Guan,
Li Qian-Kun,
Li Ai-Wu,
Yu Yan-Hao
1.College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 61590930, 91323301, 61435005, 21473076).Received Date:30 March 2017
Accepted Date:19 May 2017
Published Online:05 July 2017
Abstract:Sapphire has shown broad application prospects in military and medical fields, due to its high hardness, excellent corrosion resistance and high transmission in the infrared band. However, these characteristics have also brought about lots of difficulties in machining or chemical etching the material. Femtosecond laser processing with excellent characteristics including small heat-affected zones and high processing resolution ratio, has become an emerging field. Therefore, it has important application prospects and has found increasingly wide applications in the fields of material modification and high-quality fabrication of three-dimensional micro-nano structures and devices. In this paper, we propose a method in which femtosecond laser processing based on multi-photon absorption is used to process sapphire beyond the optical diffraction limit. In this work, femtosecond laser with a central wavelength of 343 nm is focused on the sapphire and the surface of sapphire is scanned with the high-precision piezoelectric positioning stages. Nano structures each with a width of about 61 nm are obtained, and the minimum space between the nano structures could be as short as about 142 nm. Further, the influences on the processing resolution from laser power and scanning speed are investigated and the generation mechanism for the nano-ripple structure is discussed. Finally, femtosecond laser processing on the sapphire with a resolution beyond the optical diffraction limit is achieved. This work provides a reference for processing the hard and brittle materials by femtosecond laser.
Keywords: femtosecond laser processing/
optical diffraction limit/
sapphire/
micro-nano structures
