Method for shaping Gaussian laser beam into rectangular beam with uniformly distributed energy, and application of method

Abstract

The invention provides a method for shaping a Gaussian laser beam into a rectangular beam with uniformly distributed energy by using a polynomial freeform lens system, and application of the method. The method comprises the following steps: S1, according to the law of the conservation of energy, an energy corresponding relation of the Gaussian beam on an input plane and a rectangular light spot with uniformly distributed energy on an output plane is built; S2, the mapping function relation of the beams on the input plane and the output plane is obtained; and S3, a polynomial freeform equation of a lens is selected, based on the mapping function relation of the beams on the input plane and the output plane, optical design software is utilized for optimizing the coefficient of the polynomial freeform equation, and after the Gaussian beam on the input plane passes through the polynomial freeform lens system, the Gaussian beam is shaped into the rectangular light spot with uniformly distributed energy on the output plane. According to the method provided by the invention, a rectangular laser light spot with uniformly distributed energy can be obtained, and meanwhile, the method can be applied to tests and research needing to use the rectangular uniform laser light spot, for example, the research and industrial production of laser pulse shot blasting strengthening and forming which need a square uniform laser light spot.

Description

technical field [0001] The invention relates to the technical field of laser beam shaping, in particular to a method and application for shaping a Gaussian laser beam into a rectangular beam with uniform energy distribution. Background technique [0002] The light intensity distribution of the fundamental mode laser beam is a Gaussian distribution, but in many applications it is expected that the light intensity distribution of the laser beam is uniform and the spot shape is rectangular (including square). For example, laser pulse shot peening and forming technology requires a power density greater than GW / cm 2 , a square laser beam with a pulse width of 10-30ns and uniform energy distribution. [0003] There are many ways to achieve laser beam shaping and homogenization. There are mainly aspheric lens method, aspheric mirror method, birefringent lens group method and diffractive optical element method. [0004] Aspheric lens technology to achieve laser beam shaping was f...

AI Technical Summary

Problems solved by technology

This method has the advantages of high diffraction efficiency, adjustable spot profile, etc., and can realize functions such as miniaturization, array, integration, and arbitrary wavefront transformation that are difficult to achieve with traditional optics. The disadvantage is that it is difficult to process and the laser damage threshold is low.

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