Birefringent Prism Beam Shaping for Stable Flat-Top Laser Profiles
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Solution Overview
Problem
Existing methods for creating a flat-top laser beam profile are complex, energy inefficient, require precise alignment, or are limited by the use of wavelength-sensitive optical components like optical waveplates, leading to temporal instability and limited spectral operation.
Innovation Solution
A method and system using birefringent materials, such as birefringent crystals or prisms, to split a polarized laser beam into multiple beams with orthogonal polarizations, spatially overlapping them to form a flat-top profile without optical waveplates, ensuring temporal stability and broad spectral operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If apodization with neutral density filter is used to flatten laser irradiance profile, then flat-top profile is achieved, but energy loss occurs and filter alignment is difficult to maintain
Solution Approach 1:
The patent divides the single laser beam into multiple separate beams using beam splitting optics. By segmenting the beam path and using multiple discrete beams, the system achieves flat-top profiling without requiring energy-absorbing filters, thus eliminating the energy loss associated with apodization methods.
Solution Approach 2:
The patent combines multiple separate laser beams into a single composite beam that exhibits a flat-top intensity profile. By merging multiple beams with controlled spatial arrangement and relative phases, the system creates the desired profile without energy loss, replacing the energy-dissipating filter approach.
2Shape
If diffractive optics are used to generate flat top profile, then flat-top profile is achieved, but optics manufacturing becomes difficult in low volume
Solution Approach 1:
Instead of manufacturing a single complex diffractive optical element, the patent segments the beam manipulation into multiple simpler optical components that split and steer individual beams. This segmentation allows each component to be manufactured using standard optics fabrication processes, avoiding the low-volume manufacturing difficulties of custom diffractive optics.
Solution Approach 2:
The patent replaces the need for complex diffractive optical elements with a mechanical beam splitting and steering system using standard optical components. This substitution uses conventional manufacturing techniques for optical components, making the system easier to manufacture in low volumes compared to custom diffractive optics.
3Shape
If scanning of laser output beam is used to form flat top illumination profile, then flat top profile is achieved, but expensive scanning optics are required
Solution Approach 1:
The patent segments the beam into multiple stationary beams that are spatially arranged to create the flat-top profile. This eliminates the need for scanning optics by using multiple fixed beams simultaneously, thereby reducing device complexity and removing expensive moving mechanical components.
Solution Approach 2:
Instead of using periodic scanning motion to achieve the illumination profile, the patent employs multiple beams that are continuously present and spatially arranged to create the flat-top profile. This static multi-beam approach replaces the periodic scanning action, eliminating the need for scanning optics.
4Stability of the object's composition
If optical waveplate is used in the system, then phase control is achieved, but temporal instability occurs due to sensitivity to temperature fluctuations
Solution Approach 1:
The patent extracts and removes the optical waveplate from the system, replacing phase control functionality with alternative methods that are less sensitive to temperature. By taking out the waveplate, the system eliminates the primary source of temperature-induced phase instability while maintaining the ability to control beam profiles.
Solution Approach 2:
The patent uses multiple copies of the laser beam with controlled spatial and phase relationships to achieve the desired illumination profile without relying on waveplates. By copying the beam multiple times and combining them with controlled phases, the system achieves phase control through geometric arrangement rather than wavelength-sensitive components.
5Shape
If complex system of phase retarders is used, then flat top profile is achieved, but device complexity increases
Solution Approach 1:
The patent segments the beam control function into multiple independent beam paths that are simpler to control individually. By dividing the complex phase control task into multiple simpler beam steering and combination operations, the overall device complexity is reduced while achieving the same flat-top profile result.
Solution Approach 2:
The patent replaces the complex mechanical system of phase retarders with a simplified optical system using beam splitting and spatial arrangement. This substitution eliminates multiple adjustable phase retardation components and replaces them with a more straightforward configuration of beam combiners and spatial filters, reducing device complexity.
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
Achieves a structurally simple, adjustable, and temporally stable flat-top laser beam profile with uniform irradiance distribution, free from optical interference and sensitive to temperature fluctuations, suitable for applications like flow cytometry.
Implementation Method 1
separating a polarized beam of light into multiple beams (containing a first beam having a first polarization and a second beam having a second polarization) by transmitting the polarized beam of light through a at least one optical prism
Implementation Method 2
transmitting the polarized beam of light through the birefringent material oriented to have a single optical axis thereof substantially perpendicular to a direction of propagation of the polarized beam of light
Data Source
AI summary
Methodology of forming a substantially flat-top illuminating light beam, from a beam at the laser output having a conventionally non-uniform distribution of irradiance, with the use of only a birefringent prismatic element and light-focusing optics. Preferably, the cross-sectional area of such illuminating light distribution is shaped to be elongated or even substantially rectangular to have it used advantageously in various metrological situations such as, for example, the operation of a moving particle analyzer.