Flattop Laser Beam Generation Using Lens Arrays and Beam Combining
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Solution Overview
Problem
Advanced scientific instruments employing lasers often require laser beams with a flattop intensity profile, which existing technologies struggle to achieve effectively, particularly in maintaining uniformity and power density.
Innovation Solution
The use of cylindrical lens arrays to homogenize the beam profile in the slow axis and collimate in the fast axis, combined with tilting diode lasers and polarization combining, along with dichroic mirrors to form high power uniform lines of different wavelengths, addresses the challenge of generating a flattop beam with improved uniformity and power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional laser sources are used, then laser beam generation is achieved, but the intensity profile is Gaussian rather than flattop
Solution Approach 1:
The patent segments the laser beam into multiple sub-beams using a beam splitter array, then recombines them to form a flattop profile. The Gaussian beam is divided into N sub-beams that are spatially separated and subsequently overlapped to create the desired uniform intensity distribution.
Solution Approach 2:
The patent transforms the beam profile from a single-dimensional Gaussian distribution to a two-dimensional flattop distribution by using beam splitters arranged in arrays and employing spatial separation followed by recombination in a different spatial configuration.
2Power
If multiple collimated laser beams are stacked to increase power density, then power density increases, but intensity uniformity deteriorates
Solution Approach 1:
The patent merges multiple collimated laser beams by stacking them in close proximity in the y-direction. The beam combining mechanism integrates these multiple beams while maintaining their individual characteristics, achieving high power density through constructive combination.
Solution Approach 2:
The patent applies local quality by tilting individual diode lasers relative to each other to shift the intensity peaks of each beam. This local adjustment ensures that the combined beam achieves improved uniformity of intensity across the flattop profile while maintaining high power density.
3Power
If polarization combining is used to double total power, then power increases, but system complexity increases
Solution Approach 1:
The patent uses a polarization combining cube as an intermediary device to combine two similar laser diode beams with orthogonal polarizations. This intermediary component efficiently doubles the total power while maintaining a relatively compact and manageable system architecture.
4Adaptability or versatility
If dichroic mirrors are used to form multiple wavelengths, then wavelength versatility increases, but device complexity increases
Solution Approach 1:
The patent employs dichroic mirrors to form two high power uniform lines of different wavelengths at some spacing. These mirrors serve multiple functions by reflecting certain wavelengths while transmitting others, enabling wavelength versatility within a unified optical system architecture.
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
This approach results in a high power uniform flattop laser beam with reduced intensity variation, suitable for high throughput applications, capable of delivering up to several hundred watts of power with a sizeable beam profile that can be effectively used in bio-applications.
Implementation Method 1
a pair of cylindrical lens arrays may be used to homogenize a beam profile in the slow axis (X) of the diode lasers
Implementation Method 2
a laser beam may be collimated in the fast axis (Y) by using a fast axis collimation lens
Implementation Method 3
two similar laser diode beams may be polarization combined by using a polarization combining cube to double the total power
Implementation Method 4
two high power uniform lines of different wavelengths at some spacing can be formed using dichroic mirrors
Data Source
AI summary
Devices, systems, and methods for generating high power flattop laser beams are disclosed. Schematics and arrangements of diodes, fast axis and slow axis cylindrical lens arrays, collimation lenses, and other optics are described and disclosed. Also disclosed are methods of generating flattop beams for myriad applications.