Compact LIBS Apparatus Using Tunable Lens for Rough Surface Analysis
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Solution Overview
Problem
Existing LIBS systems face challenges with low power lasers, requiring high power density for plasma ignition, leading to localized measurements, inefficiencies in rough surface analysis, and sensitivity to sample cleanliness and homogeneity, with prior methods offering limited resolution and practicality for non-smooth surfaces.
Innovation Solution
A compact LIBS apparatus using an electrically tunable focusing lens and achromatic reflective optics to optimize laser fluence and plasma generation, employing the ratio of ionic to atomic lines for precise focusing and maximizing ablation efficiency, and incorporating multiple sampling points for accurate analysis on uneven surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a lower power laser is used, then the apparatus can be more compact, but the ablation area is reduced and detection reliability decreases
Solution Approach 1:
The patent changes the focal length parameter of the lens to optimize the laser spot size on the sample surface. By adjusting the focal length dynamically, the system maintains sufficient ablation area and plasma generation even with lower power lasers, thereby preserving detection reliability while enabling compact apparatus design.
Solution Approach 2:
The patent employs a dynamically adjustable lens focal length that can be modified in real-time based on sample characteristics and laser power conditions. This dynamic adjustment allows the system to adapt to varying conditions and maintain optimal performance with compact, lower-power laser sources.
2Power
If the laser spot size is reduced to increase power density, then plasma ignition is achieved, but the measurement becomes more localized and less representative
Solution Approach 1:
The patent uses dynamic focal length adjustment to balance spot size and power density. By optimizing the focal length, the system achieves sufficient power density for plasma ignition while maintaining an appropriate spot size that provides representative measurements of the bulk material rather than highly localized spots.
Solution Approach 2:
The system modifies the focal length parameter to control the laser spot characteristics. This parameter change enables optimization of both power density and spot size, achieving plasma ignition conditions while ensuring the measurement area is sufficiently large to be representative of the bulk material.
3Productivity
If the focal length is adjusted for rough surfaces, then ablation efficiency improves, but the system complexity increases
Solution Approach 1:
The patent implements a dynamically adjustable lens focal length mechanism that can adapt to different sample surface conditions including rough surfaces. This dynamic capability improves ablation efficiency by maintaining optimal focus on the sample surface regardless of surface topology, while the design keeps the complexity manageable through focused implementation.
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 solution enhances the precision and reliability of LIBS analysis on rough surfaces by achieving higher laser fluence and plasma generation efficiency, improving measurement accuracy and sensitivity, and accommodating varying sample cleanliness and homogeneity.
Implementation Method 1
LIBS involves focussing a laser on a target sample in order to generate sufficient heat to create ablation
Implementation Method 2
generate sufficient heat to create ablation (i.e. material removal by vaporization of said material)
Implementation Method 3
as the plasma cools, electrons from the various elements that comprise the sample fall from various excited states to lower energy states, emitting photons in the process
Data Source
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AI summary
The present invention provides a method and compact apparatus for laser induced breakdown atomic emission spectroscopy from a targeted sample having a laser generating a laser beam, the laser beam directed to the sample, optical means for manipulating the laser beam in order maximize laser fluency at the target surface of the sample, the laser beam generating ablation and plasma emission from the sample at the target surface, an emission spectrometer having a detector for detecting a plasma plume from the plasma emission.