Bessel Beam Optical Layout for Homogeneous Laser Processing
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Solution Overview
Problem
Laser processing apparatuses using pulse wave lasers often cause filamentation phenomena in transparent materials like glass, leading to non-homogeneous laser beam outputs.
Innovation Solution
An optical system comprising a phase retardation plate, axicon lens, collimating lens, polarizing beam splitter, and focusing lens, arranged in a 4f optical setting, to generate a homogeneous output laser beam by converting a Gaussian beam into multiple Bessel beams with controlled polarization and spacing, minimizing destructive interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pulse wave laser is used for laser processing, then the laser can cause filamentation phenomenon in transparent materials, but the output laser beam becomes non-homogeneous
Solution Approach 1:
The patent divides a single laser beam into multiple Bessel beams (first, second, and third Bessel beams) with different characteristics. By segmenting the beam path and using multiple optical elements (axicon lens, collimating lens, focusing lens), the system creates separate beam components that are later recombined to form a homogeneous output beam, thus resolving the non-homogeneity issue while maintaining processing capability
Solution Approach 2:
The patent combines multiple Bessel beams (first, second, and third Bessel beams) generated through different optical paths into a single composite laser beam. The collimating lens and focusing lens merge these segmented beams while maintaining their individual characteristics, resulting in a homogeneous output beam that retains the filamentation capability needed for transparent material processing
2Use of energy by moving object
If multiple Bessel beams are combined to increase energy density, then the output beam becomes more concentrated, but interference patterns may reduce homogeneity
Solution Approach 1:
The patent changes key parameters of the Bessel beams including cone angles, beam diameters, and spacing between beams. By carefully controlling these parameters through the optical system design, the multiple Bessel beams are combined in a way that maximizes energy density while minimizing interference patterns, achieving both high concentration and uniform intensity distribution in the output beam
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system produces a composite Bessel beam with high energy density and uniform intensity distribution, effectively avoiding filamentation and enhancing laser processing precision.
Implementation Method 1
a phase retardation plate which controls a polarization of an input laser beam
Implementation Method 2
an axicon lens disposed to be spaced apart from the phase retardation plate on an emitting surface side of the phase retardation plate, wherein the axicon lens converts the input laser beam into a single first Bessel beam having a single cone angle
Implementation Method 3
a collimating lens disposed to be spaced apart from the axicon lens on an emitting surface side of the axicon lens, wherein the collimating lens collimates the single first Bessel beam in a form of a single second Bessel beam having an annular energy distribution
Implementation Method 4
a polarizing beam splitter disposed to be spaced apart from the collimating lens on an emitting surface side of the collimating lens, wherein the polarizing beam splitter splits the single second Bessel beam into a plurality of third Bessel beams having different polarization directions from each other
Implementation Method 5
a focusing lens disposed to be spaced apart from the polarizing beam splitter on an emitting surface side of the polarizing beam splitter, wherein the focusing lens focuses the plurality of third Bessel beams to form an output laser beam
Data Source
AI summary
An optical system includes a phase retardation plate which controls a polarization of an input laser beam, an axicon lens spaced apart from the phase retardation plate on an emitting surface side thereof to convert the input laser beam into a single first Bessel beam having a single cone angle, a collimating lens spaced apart from the axicon lens on an emitting surface side thereof to collimate the single first Bessel beam in a form of a single second Bessel beam having an annular energy distribution, a polarizing beam splitter spaced apart from the collimating lens on an emitting surface side thereof to split the single second Bessel beam into third Bessel beams having different polarization directions, and a focusing lens spaced apart from the polarizing beam splitter on an emitting surface side thereof to focus the plurality of third Bessel beams to form an output laser beam.