Rectangular Flat-Top Beam Shaper Using Orthogonal Acylindrical Lenses
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Solution Overview
Problem
Existing laser beam shaping technologies, such as diffractive and refractive optics, are inadequate for producing uniform intensity profiles for non-rotationally symmetric laser beams, particularly from laser diodes, due to wavelength dependency and inefficiency, and are not suited for wide spectrum or multiple wavelength applications.
Innovation Solution
A beam shaping system utilizing two orthogonally disposed acylindrical lenses with variable curvature and conic constants, along with correction functions, to independently shape the intensity profile along two perpendicular axes, creating a rectangular beam with controlled intensity distribution, suitable for both far-field and near-field applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If diffractive beam shapers are used to shape Gaussian-like laser beams, then a flat-top laser beam can be provided, but wavelength dependency and low efficiency occur making them unsuitable for wide spectrum or multiple wavelength illumination
Solution Approach 1:
The patent replaces diffractive optical elements with refractive acylindrical lenses. The refractive system uses continuous variation of radius of curvature along the cylindrical axis to shape the beam profile, eliminating the wavelength-dependent diffraction effects while maintaining the flat-top beam shape capability across multiple wavelengths.
Solution Approach 2:
The patent changes the optical parameter from diffraction-based to refraction-based by using acylindrical lenses with specifically designed radius of curvature profiles. The radius of curvature varies continuously along the cylindrical axis according to specific mathematical functions, enabling wavelength-independent beam shaping.
2Use of energy by moving object
If conventional refractive techniques using aspherical lenses are used, then efficient beam shaping with low wavelength dependency is achieved, but they are not adapted to shape non-rotationally symmetrical laser diode beams
Solution Approach 1:
The patent introduces asymmetry by using acylindrical lenses instead of rotationally symmetrical aspherical lenses. The acylindrical lenses have different curvature radii in orthogonal directions, with the radius of curvature varying along the cylindrical axis according to specific functions, enabling independent control of beam shaping in two perpendicular planes to handle elliptical laser diode beams.
Solution Approach 2:
The patent segments the beam shaping function into two independent acylindrical lenses oriented perpendicularly to each other. Each lens handles one principal axis of the elliptical beam, with the first lens shaping along the major axis and the second lens shaping along the minor axis, allowing independent optimization for non-rotationally symmetrical beams.
3Shape
If acylindrical lenses with high divergence are used to provide long laser lines, then uniform intensity distribution is achieved, but the line length becomes excessively long and thin
Solution Approach 1:
The patent optimizes the radius of curvature parameter of the acylindrical lenses to achieve the desired balance. By carefully selecting the radius of curvature profile according to specific mathematical functions and optimizing it for the desired line length and uniformity, the system achieves uniform intensity distribution without excessive line length extension.
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 effectively transforms non-uniform laser beams into rectangular beams with controlled intensity profiles, maintaining uniformity over significant distances and allowing for efficient illumination of submillimeter targets, while being adaptable to various wavelengths.
Implementation Method 1
Refractive beam shaping techniques are efficient and provide low wavelength dependency. Conventional refractive techniques using aspherical lenses are suitable for generating a rotationally symmetrical flat-top beam from a rotationally symmetrical Gaussian input beam
Data Source
AI summary
The invention relates to a beam shaping system for providing a square or rectangular laser beam having a controlled intensity profile (uniform, super gaussian or cosine corrected for example) from an incident non-uniform beam intensity profile laser beam source (a Gaussian profile, a profile with astigmatism or any non-rotationally symmetric and non-uniform profile for example). The beam shaping system uses a first acylindrical lens for shaping the incident laser beam along a first axis and a second acylindrical lens orthogonally disposed relative to the first acylindrical lens and for shaping the incident beam along a second axis. The thereby provided light beam is a rectangular beam having a controlled intensity distribution in the far field.