Method for determining laser defocusing amount in femtosecond laser polishing process of optical element

A femtosecond laser and optical element technology, applied in laser welding equipment, complex mathematical operations, manufacturing tools, etc., can solve the problems of high cost, poor accuracy and low efficiency of polishing defocus, and achieve high efficiency and high accuracy. , the effect of low cost

Pending Publication Date: 2020-07-03
TIANJIN UNIV
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Problems solved by technology

[0005] In order to solve the problem of high cost, low efficiency and poor accuracy of determining the appropriate polishing defocus amount for existing femtosecond laser polishing optical components, the present invention proposes a method combining mathematical models and calculation methods to quickly and accurately calculate Laser polishing distance from suitable focus under process conditions

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  • Method for determining laser defocusing amount in femtosecond laser polishing process of optical element
  • Method for determining laser defocusing amount in femtosecond laser polishing process of optical element
  • Method for determining laser defocusing amount in femtosecond laser polishing process of optical element

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Embodiment 1

[0033] see figure 1 , a method for determining the amount of laser defocus in the process of femtosecond laser polishing optical components, a method for determining the amount of laser defocus in the process of femtosecond laser polishing optical components, comprising the following steps:

[0034] A. Use the femtosecond laser to output the laser wavelength λ(m), and the focus spot radius r(m) to calculate the Rayleigh length ZR(m) of the beam,

[0035] B. Use the output pulse energy F(J) of the laser to focus the spot radius r(um) and the defocus amount Z(um) to calculate the energy density F`(J / um) when the laser reaches the surface of the material 2 ),

[0036] C. Calculate the ablation depth L (m) on the surface of the energy material by using the femtosecond laser ablation rate mathematical model, where the ablation rate mathematical model is:

[0037]

[0038] In the formula, L is the ablation depth; h is Planck's constant; ω is the laser frequency; τ is the la...

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Abstract

The invention discloses a method for determining the laser defocusing amount in the femtosecond laser polishing process of an optical element, which belongs to the technical field of mechanical precision manufacturing engineering, and comprises the following steps of: outputting laser wavelength and focusing spot radius by using a femtosecond laser, and calculating Rayleigh length of a light beam;calculating the energy density when the laser reaches the surface of the material by utilizing the output pulse energy of the laser to focus the spot radius and the defocusing amount; calculating theablation depth of the surface of the energy material by using a femtosecond laser ablation rate mathematical model; solving the ablation depth of the femtosecond laser to the material under differentdefocusing amounts according to the laser ablation rate mathematical model; measuring the average value of the surface of the to-be-polished optical element, and determining the optimal polishing defocusing amount by substituting the height difference of the wave crest and the wave trough into calculation. The defocusing amount of femtosecond laser polishing can be rapidly, efficiently and accurately determined, the cost is low, the efficiency is high, and the accuracy is high.

Description

technical field [0001] The invention relates to the technical field of mechanical precision manufacturing engineering, and more specifically, relates to a method for determining the amount of laser defocus in the process of femtosecond laser polishing optical elements. Background technique [0002] The precision forming technology of optical materials pays attention to its size, properties and surface roughness to meet the corresponding strict manufacturing requirements. The processing characteristics of optical materials are hard and brittle materials, which are not easy to deform under the action of external force and have low fracture toughness. The elastic limit and strength of materials are close. There are currently three types of polishing methods for optical components. The first is conventional mechanical polishing, the second is plasma beam polishing, and the third is laser polishing. The traditional mechanical processing method is often "head-to-head". Such proce...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/10B23K26/352
CPCG06F17/10B23K26/3576
Inventor 吕可鑫韩雪松
Owner TIANJIN UNIV
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