Citation: | Zhang Z Y, Chen M, Wang C L, et al. Research on shaping characteristics of Gaussian beam aspheric shaping system[J]. Opto-Electron Eng, 2022, 49(4): 210367. doi: 10.12086/oee.2022.210367 |
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The method of using an aspheric lens to shape Gaussian beam has been very mature. A specific aspheric shaping mirror can be designed according to the incident light parameters to shape the Gaussian beam into a flat-top beam so that the laser can be better applied to laser medicine, laser processing and other fields. Aspheric mirror shaping has the advantages of simple structure, high damage threshold and high shaping efficiency. At present, the research on the aspherical shaping system lies in the design of its structure, and there is no detailed study on its shaping characteristics. Therefore, this paper focuses on the shaping effect of the aspherical shaping system under different incident parameters.
These aspheric systems have two kinds of structures, one is the Galileo type, and the other is the Kepler type. The Galileo lens has no focus between two lenses, so it is suitable for high power laser shaping. In this paper, a Galileo aspheric shaping mirror with an incident beam waist of 3 mm is used for the experiment. It is found that the aspheric shaping mirror is not only suitable for the design of incident parameters. When the incident beam size and divergence angle are different, flat-top distribution will appear after the shaping mirror. The position is away from the shaping mirror with the increase of the diameter of the incident beam, and close to the shaping mirror with the increase of the divergence angle. In order to explore the difference in shaping results on the optimal shaping position, the control variable method is used to carry out the experiment. It is found that the diameter and divergence angle of the incident light beam have no obvious change in the flat factor of the flat top distribution on the position, but the beam uniformity and edge steepness will have the best value, and there is an optimal incident parameter. In order to obtain the relationship between the optimal shaping position and the diameter and divergence angle of the incident beam, the mathematical model is successfully established by using the response surface method. When the diameter and divergence angle of the beam at an incident position are known, the optimal shaping position can be quickly obtained. The discovery is of great significance to the aspherical shaping mirror that has been designed and fabricated. It shows that an aspherical shaping mirror can shape the laser with different incident parameters and make the use of the shaping mirror more convenient.
Illustration for a uniform energy density distribution H(x) in one dimension
Structure of aspheric shaping system
Experimental device diagram
Laser power stability test
Light intensity distribution maps corresponding to different incident beam diameters.
Fitting curves of incident beam diameter with optimal shaping position, flatness factor, beam uniformity and edge steepness.
Light intensity distributions corresponding to different incident divergence angles.
Fitting curve of incident divergence angle with optimal shaping position, flatness factor, beam uniformity and edge steepness.