LIBS Detection Optics for Structured Surface Analysis
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Solution Overview
Problem
Existing LIBS systems struggle with analyzing samples having structured, undefined surface profiles, leading to insufficient detection signals and requiring complex sample handling.
Innovation Solution
A spectrometer system with multiple lenses and an optical light guidance system that captures plasma light from multiple detection zones along the laser beam axis, allowing for flexible sample positioning and enhanced plasma light detection without mechanical adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single detection zone is used in conventional LIBS systems, then the system structure is simple, but the detectable depth of field is limited and samples with structured surfaces cannot be reliably analyzed
Solution Approach 1:
The detection system is divided into multiple independent detection zones (first, second, and third detection zones) arranged at different positions along the beam axis. Each detection zone is equipped with its own objective lens and detection cone, allowing simultaneous detection of plasma light from multiple depths. This segmentation enables reliable analysis of samples with structured surfaces by capturing plasma signals from different focal planes.
Solution Approach 2:
The detection zones are arranged in the depth dimension (along the beam axis) rather than only in the lateral plane. By extending detection coverage along the beam axis at different distances from the sample surface, the system achieves three-dimensional detection coverage, increasing the detectable depth of field and enabling analysis of samples with varying surface heights.
2Length of stationary object
If multiple lenses are used to increase detection zones, then the detectable depth of field increases, but the optical system complexity increases
Solution Approach 1:
Multiple detection zones with different objective lenses are merged into a single integrated detection system. The plasma light detected by each objective lens is combined and transmitted through a common light guidance system (optical fibers or lenses) to a single spectrometer. This merging approach increases the detectable depth of field while avoiding the complexity of multiple independent spectrometers.
Solution Approach 2:
The spectrometer serves multiple functions by receiving plasma light from multiple detection zones simultaneously. A single spectrometer is designed to handle combined light inputs from different optical paths, enabling it to analyze plasma signals from various depths and sample regions, thus achieving multi-functional detection capability.
3Ease of operation
If the detection unit is fixed in position, then the system is simple to operate, but samples with non-uniform surfaces produce shadowing effects and insufficient detection signals
Solution Approach 1:
The detection system is segmented into multiple spatially separated detection zones with different viewing angles and focal distances. This segmentation allows each detection zone to capture plasma light from different regions of the sample surface, reducing shadowing effects caused by non-uniform surfaces and ensuring reliable signal detection without requiring complex mechanical adjustments.
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 reliable analysis of samples with non-uniform surfaces by increasing the detectable depth of field and reducing shadowing effects, facilitating sample preparation-free analysis of both stationary and flowing samples.
Implementation Method 1
a laser beam source for emitting laser radiation, in particular for emitting a pulsed laser beam
Implementation Method 2
depending on the laser parameters of the laser beam and the sample material, a plasma ignition region forms along the beam axis such that a surface of the sample located within this region leads to the formation of a laser-induced plasma
Implementation Method 3
Light emitted by the plasma is detected and spectrally analyzed to deduce the elemental composition of the sample
Implementation Method 4
The detection unit comprises a lens holder and several lenses held by the lens holder. Each objective lens is assigned a detection cone that forms a plasma detection zone
Implementation Method 5
an optical light guidance system with several optical inputs and one optical output... Each optical input is optically assigned to one of the objective lenses and is designed to receive a measurement component detected by the assigned objective lens
Data Source
Figure 1
Figure 2~3
Figure 4A~6B
AI summary
The invention relates to a spectrometer system (201) for laser-induced plasma spectral analysis, comprising a laser beam source (209) for emitting a laser beam (205) and a focusing optical unit (211) for focusing the laser beam (205) on a sample. A plasma generation region is formed such that a surface of the sample (7) which is located in the plasma generation region leads to the formation of a laser-induced plasma (3). The spectrometer system (201) also comprises a detection unit (221) for capturing plasma light. The detection unit (221) comprises a plurality of objectives (225A, 225B, 225C, 225D). Each of the objectives (225A, 225B, 225C, 225D) is associated with a detection cone (235) which, in a region of overlap with the laser beam (205), forms a plasma detection region (239), such that, when the laser induced plasma (3) is formed in one of the plasma detection regions (239), a measurement component of the plasma light can be captured by the corresponding objective (225A, 225B, 225C, 225D). The plasma detection regions (239) jointly form a field of vision (241) of the detection unit (221). The spectrometer system (201) also comprises a sample vessel (203), a sample vessel support (271, 271') and an optical spectrometer (213) for the spectral analysis of the measurement components of the plasma light which are captured by the detection unit (221). The sample vessel support is designed to move the sample vessel (203) such that e.g. in a measurement process for spectral analysis a plurality of portions of the surface of the sample (7) can be positioned in the plasma generation region.