Research On The Mechanism And Process Parameters Of Femtosecond Laser Processing Of Glass Microstructure

BOROFLOAT?33(BF33)produced by German SCHOTT is a high-quality borosilicate glass material,which has the advantages of high light transmittance,low thermal expansion coefficient,strong heat resistance,and good chemical stability.It is widely used in aeronautics and astronautics,electrical and electronic,MEMS device packaging,biomedical and optical fields.However,at this stage,there are still great difficulties in realizing the microstructure processing of hard and brittle materials such as glass,and traditional mechanical processing methods cannot meet the requirements of fine glass processing.At present,femtosecond laser as an emerging processing method has great application prospects.Because of its extremely short pulse width and extremely high single pulse energy,it has significant advantages for high-precision micro-nano processing of hard,brittle and high melting point materials.Therefore,this paper uses femtosecond laser technology to process the microstructure of BF33 borosilicate glass.By analyzing the mechanism of femtosecond laser ablation of transparent dielectrics,a physical model is established,and the theoretical ablation threshold is simulated.Through femtosecond laser multi-pulse cumulative ablation experiment,solve the experimental ablation threshold.Through single factor experiment and orthogonal experiment to optimize the laser parameters,get the optimal laser processing parameters of the microlens array structure,and finally carry out the hydrofluoric acid corrosion experiment to get the smooth microlens array.The main research contents are as follows:(1)According to the relationship equation of the electron density of transparent dielectric materials with time and the theory of avalanche ionization and multiphoton ionization,a physical model of femtosecond laser ablation of BF33 borosilicate glass was established,and BF33 borosilicate glass was ablated by MATLAB the threshold value is programmed and calculated,and the theoretical value is obtained.(2)Carry out multi-pulse cumulative ablation experiments under different repetition frequencies,and calculate the ablation threshold of BF33 borosilicate glass according to the super-depth microscope image and mathematical model,obtain the experimental value,and analyze the material ablation threshold under the action of multiple pulses change characteristics.(3)Through single-factor femtosecond laser ablation experiments,the influence of laser power,repetition frequency,scanning speed and scanning times on the ablation quality of BF33 borosilicate glass was obtained,and the optimal laser was obtained through multi-factor orthogonal experiments.The processing parameters were verified by experiments to compare the laser processing morphology before and after optimization.(4)Based on the optimized experimental parameters,the influence of laser parameters on the roundness,diameter and depth of the microlens is further explored,and the best microlens processing parameters are obtained through comprehensive analysis.The depth of 15μm is obtained by using the laser parameters.Microlens with a diameter of 33.4μm(depth-to-diameter ratio is about 1:2)and its array structure,and the changes of the microlens diameter and surface morphology with the hydrofluoric acid etching time are explored,and finally the optics of the microlens array Performance was tested.