Laser Beam Analysis Using Fabry-Perot Resonator
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Solution Overview
Problem
Conventional apparatuses for analyzing low power laser beams are bulky, require multiple moving parts, and cannot perform real-time analysis using the optical components of conventional material processing systems, limiting their effectiveness in measuring laser beams with short focal lengths and necessitating offline measurements.
Innovation Solution
A compact apparatus utilizing a Fabry-Perot resonator with anti-reflection and highly reflective coatings, paired with a focusing lens and polarizers, and a pixelated detector to analyze laser beams in situ, minimizing optics and eliminating moving parts for real-time measurement of beam properties like spatial profile, circularity, and M2 values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional apparatus with multiple moving parts is used to analyze laser beams, then the measurement can be performed, but the device becomes bulky and cannot perform real-time analysis
Solution Approach 1:
The patent replaces mechanical moving parts with a fixed optical system. The Fabry-Perot interferometer uses fixed mirrors and a stationary optical path to achieve beam analysis without any moving components, eliminating the contradiction between real-time measurement capability and device complexity.
Solution Approach 2:
The optical system is segmented into distinct functional components (Fabry-Perot interferometer, focusing lens, polarizers, detector) that work together in a fixed configuration. This segmentation allows each component to perform its specific function efficiently without requiring mechanical movement, enabling real-time analysis while maintaining simplicity.
2Adaptability or versatility
If multiple optics are stacked to analyze laser beams, then beam analysis is possible, but the beam waist that can be measured is limited and fabrication becomes difficult
Solution Approach 1:
The patent introduces a Fabry-Perot interferometer as an intermediary optical element that replaces the need for stacking multiple thick plates. The interferometer uses thin partially reflective coatings on transparent substrates, making it easier to fabricate while expanding the range of measurable beam waists through adjustable optical path differences.
Solution Approach 2:
The system changes the parameter of plate thickness to thin substrates with reflective coatings, and uses the adjustable spacing in the Fabry-Perot cavity to vary the effective optical path. This allows measurement of various beam waists without requiring thick stacked plates, improving ease of manufacture while maintaining versatility.
3Measurement precision
If a rotating needle apparatus is used to measure beam waist, then the measurement can be performed, but the device requires many moving parts and is bulky
Solution Approach 1:
The patent replaces the mechanical rotating needle system with a stationary Fabry-Perot interferometer. The interferometer uses fixed mirrors and optical interference to measure beam properties with high precision, eliminating all moving parts while maintaining measurement accuracy.
Solution Approach 2:
Instead of physically moving a needle through the beam, the system uses optical interference patterns created by the Fabry-Perot cavity to create a measurement equivalent to the rotating needle method. The interference fringes provide the same beam waist information without mechanical movement, reducing device complexity while preserving measurement precision.
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
Enables real-time, in-situ analysis of low power laser beams with minimal optics, providing accurate data on beam properties without moving parts, suitable for conventional material processing systems, and capable of measuring beams with short focal lengths.
Implementation Method 1
a Fabry-Perot resonator including a first mirror having an anti-reflection coating on a first surface thereof that faces the source of the laser beam and a non-absorbing, highly reflective coating that transmits less than one percent (1%) of said laser beam on a second surface thereof that faces away from the source
Implementation Method 2
a first mirror having an anti-reflection coating on a first surface thereof that faces the source of the laser beam
Implementation Method 3
a non-absorbing, highly reflective coating that transmits less than one percent (1%) of said laser beam
Data Source
AI summary
An apparatus having a linear structure that enables real time measurement of the spatial profile, circularity, centroid, astigmatism and M2 values of a laser beam generated by a low power laser beam. A laser beam source transmits a laser beam through a focusing lens, a Fabry-Perot resonator, a pair of polarizers and a camera that detects spots of light that pass through the first and second mirrors and the polarizers. The resonator includes a pair of high reflecting mirror plates disposed in parallel, spaced apart relation to one another at a common angle of incidence to the laser beam. The polarizers are disposed at an opposite angle of incidence and are rotationally adjustable to enable intensity adjustment of the camera.