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CN-122007600-A - Laser processing device and laser processing method

CN122007600ACN 122007600 ACN122007600 ACN 122007600ACN-122007600-A

Abstract

The application discloses a laser processing device and a laser processing method, and relates to the field of laser processing, wherein the device comprises a composite beam shaper, a laser processing device and a laser processing device, wherein the composite beam shaper comprises a substrate, a diffraction optical element and a super surface, and the diffraction optical element and the super surface are respectively positioned at two sides of the substrate; the composite beam shaper regulates and controls the phase distribution of the composite beam shaper by changing at least one of the length of the superatoms in the two orthogonal directions, the azimuth angle of the superatoms and the height of the structural units in the diffractive optical element in the supersurface, and converts the incident beam into a target flat-top beam. A composite beam shaping device is generated by combining a diffractive optical element with the supersurface, thereby shaping the laser Gaussian energy distribution into a flat-top uniform energy distribution. The composite beam shaping device is used for replacing a beam shaping element and an objective lens in a traditional laser processing system, so that the problems of huge volume, complex optical path and the like inherent in the traditional beam shaping system can be solved, and the miniaturization and integration of a processing device are realized.

Inventors

  • LI MING
  • LI YUNXIAO
  • Feng Tianli
  • LI TAO
  • YANG KEJIAN

Assignees

  • 山东大学

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. A laser processing apparatus, comprising: The composite beam shaper comprises a substrate, a diffraction optical element and a super surface, wherein the diffraction optical element and the super surface are respectively positioned at two sides of the substrate; The composite beam shaper regulates and controls the phase distribution of the composite beam shaper by changing at least one of the length of the super atoms in the super surface in two orthogonal directions, the azimuth angle of the super atoms and the height of the structural units in the diffraction optical element, and converts an incident beam into a target flat-top beam.
  2. 2. The laser processing apparatus according to claim 1, wherein a phase expression of a left-hand circular polarization component in an exit field of the compound beam shaper is: Wherein, the Is a phase expression of the left-hand circular polarization component, Is the transmission phase of the super atom, Representing the effective index of refraction of the superatom, the size of which is related to the length of the superatom in two orthogonal directions within the supersurface, Representing the height of the superatom; providing phase compensation for the phase of the diffractive optical element, for the compound beam shaper, For the effective refractive index of the structural units within the diffractive optical element, Height of the structural unit of the diffraction optical element; Is the azimuth of the super atom.
  3. 3. The laser processing apparatus according to claim 1, wherein a phase expression of a right-handed circular polarization component in an exit field of the compound beam shaper is: Wherein, the Is a phase expression of the right-hand circular polarization component, Is the transmission phase of the super atom, Representing the effective refractive index of the structural element, the size of which is related to the length of the superatom in the supersurface in two orthogonal directions, Representing the height of the superatom; providing phase compensation for the phase of the diffractive optical element, for the compound beam shaper, For the effective refractive index of the structural units within the diffractive optical element, Height of the structural unit of the diffraction optical element; Is the azimuth of the super atom.
  4. 4. The laser processing apparatus of claim 1, wherein the type of material of the substrate, the diffractive optical element, and the supersurface is a dielectric material.
  5. 5. The laser processing apparatus of claim 1, wherein the super-atomic structure in the super-surface is rectangular or elliptical; the period of the super atoms in the super surface is 660nm, and the height is 900nm; the period of the diffractive optical element is 660nm.
  6. 6. The laser processing device of claim 1, further comprising at least one of a beam expander, a wave plate set, and a triaxial displacement stage; The beam expander is used for expanding the light spot of the incident laser to a preset size; The wave plate group is used for adjusting the polarization state of the incident laser to be the type of circularly polarized light of the incident laser, and the type of circularly polarized light comprises at least one of left circularly polarized light and right circularly polarized light; the triaxial displacement platform is used for controlling the movement of the workpiece to be processed.
  7. 7. The laser processing device of claim 6, wherein the waveplate set comprises at least one of a half waveplate and a quarter waveplate.
  8. 8. A laser processing method, characterized by being applied to the laser processing apparatus as claimed in any one of claims 1 to 7, the method comprising: determining a holographic phase of a target flat-top beam based on a shape of the target flat-top beam; Determining a composite beam shaper parameter based on the circularly polarized light type of the target flat-top beam and the holographic phase; the compound beam shaper parameters include at least one of a length of a superatom in two orthogonal directions within a supersurface, a superatom azimuth angle, and a height of a structural unit within a diffractive optical element.
  9. 9. The method according to claim 8, wherein said determining the composite beam shaper parameters based on the circularly polarized light type of the target flat top beam and the holographic phase, comprises: based on the focal length and the wavelength of the incident light source, determining lens phases corresponding to the left-hand circle component and the right-hand circle component of the emergent field of the composite beam shaper respectively; based on the lens phase, the holographic phase and the circularly polarized light type, a composite beam shaper parameter is determined.
  10. 10. The method of claim 9, wherein the expression for the lens phase is: Wherein, the For the phase of the lens, As the focal length of the lens is, The radius is the radius corresponding to the lens phase; indicating the wavelength of the incident light source.

Description

Laser processing device and laser processing method Technical Field The application relates to the field of laser processing, in particular to a laser processing device and a laser processing method. Background In laser processing, the characteristics of the laser beam play a critical role in determining the quality and performance of the manufactured part. Gaussian beams are widely used in laser systems, with energy distributions similar to gaussian curves. Gaussian beams are ideal for laser processing applications by virtue of their excellent beam quality, low divergence and high spatial coherence. However, with the development of laser processing technology and the growing demand for higher productivity and high quality workpieces, the limitations of conventional gaussian beams have become more and more apparent. These limitations result from steep energy gradients in the beam out-diffusion from the center, directly affecting process stability, productivity, mechanical properties, surface roughness, and the microstructure of the fabricated part. Therefore, there is a need for spatial beam shaping techniques to tailor the laser intensity to a uniform spatial distribution. The existing shaping laser processing system is generally composed of a beam homogenizer or a spatial light modulator, and the system occupies huge space, has complex light path design and complex debugging process. Disclosure of Invention In order to solve the above problems, the present application proposes a laser processing apparatus including: The composite beam shaper comprises a substrate, a diffraction optical element and a super surface, wherein the diffraction optical element and the super surface are respectively positioned on two sides of the substrate, and the composite beam shaper regulates and controls the phase distribution of the composite beam shaper by changing at least one of the length of super atoms in the super surface in two orthogonal directions, the azimuth angle of the super atoms and the height of a structural unit in the diffraction optical element, so that an incident beam is converted into a target flat-top beam. In one example, the phase expression of the left-hand circular polarization component in the exit field of the composite beam shaper is: Wherein, the Is a phase expression of the left-hand circular polarization component,Is the transmission phase of the super atom,Representing the effective index of refraction of the superatom, the size of which is related to the length of the superatom in two orthogonal directions within the supersurface,Representing the height of the superatom; providing phase compensation for the phase of the diffractive optical element, for the compound beam shaper, For the effective refractive index of the structural units within the diffractive optical element,Height of the structural unit of the diffraction optical element; Is the azimuth of the super atom. In one example, the phase expression of the right-hand circular polarization component in the exit field of the composite beam shaper is: Wherein, the Is a phase expression of the right-hand circular polarization component,Is the transmission phase of the super atom,Representing the effective refractive index of the structural element, the size of which is related to the length of the superatom in the supersurface in two orthogonal directions,Representing the height of the superatom; providing phase compensation for the phase of the diffractive optical element, for the compound beam shaper, For the effective refractive index of the structural units within the diffractive optical element,Height of the structural unit of the diffraction optical element; Is the azimuth of the super atom. In one example, the type of material of the substrate, the diffractive optical element, and the supersurface is a dielectric material. In one example, the super-atomic structure in the super-surface is rectangular or elliptical, the period of the super-atoms in the super-surface is 660nm, the height is 900nm, and the period of the diffractive optical element is 660nm. In one example, the laser processing device further comprises at least one of a beam expander, a wave plate set and a triaxial displacement platform, wherein the beam expander is used for expanding a light spot of incident laser to a preset size, the wave plate set is used for adjusting the polarization state of the incident laser to a circularly polarized light type of the incident laser, the circularly polarized light type comprises at least one of left circularly polarized light and right circularly polarized light, and the triaxial displacement platform is used for controlling movement of a workpiece to be processed. In one example, the wave plate set includes at least one of a half wave plate and a quarter wave plate. The application also provides a laser processing method which is applied to the laser processing device in any example, and comprises the steps of determin