Research On Laser Direct Writing System And Error Based On Galvanometer Scanning

Owing the characteristics of high precision,fast processing efficiency and high freedom of three-dimensional design,femtosecond laser direct writing technology based on two-photon absorption was widely used in the processing of various micro-optical devices.In order to improve the processing efficiency and quality of laser direct writing technology,this project added a scanning galvanometer to the original femtosecond laser direct writing system for upgrading.At the same time,a detailed study of the image field distortion of the galvanometer scanning was carried out,and various errors were analyzed.For the reasons,the corresponding correction method was proposed and realized.The main work of the thesis includes the following two aspects:(1)The upgrade of the femtosecond laser direct writing system based on galvanometer scanning was completed.According to the processing requirements of optical micro-nano devices,based on the original system parameters,hardware such as galvanometer,acoustooptic modulator and camera were selected to build the upgrade system,and the control software based on Lab VIEW was updated.The elliptical spiral phase plate was processed by the upgraded system.The experimental results showed that the scanning speed of laser direct writing reaches 100mm/s,which not only greatly improves the processing efficiency,but also improved the processing quality of the phase plate while shortening the processing time,thus verifying the feasibility of upgrading the laser direct writing system.(2)Error simulation analysis and correction were carried out on the upgraded system.The optical principle of galvanometer scanning was simulated by matlab,and the causes of image field distortion was analyzed,which was corrected by the grid correction method;the problem of the inclination of the processing plane was also analyzed and corrected.Finally,the tilt error of the scanning splicing process of the displacement platform and the galvanometer was corrected,and the feasibility of the splicing process was verified by the square processing.