Multiple Laser Cavity Enhanced Absorption Spectroscopy

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Solution Overview

Problem

Existing gas analysis systems face challenges in accurately measuring concentrations of gases with absorption lines in different spectral regions, as they often require expensive and impractical cavity mirrors or multiple optical cavities, which increases costs and complexity.

Innovation Solution

The use of multiple coherent light sources coupled to a single resonance optical cavity through cavity coupling mirrors, allowing for the sharing of gas volume between optical cavities and reducing the need for expensive modules, with methods to combine laser beams using beam splitters and filters, and locking the cavity to absorption lines for precise measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple optical cavities are used to measure gases in different spectral regions, then measurement capability for multiple gas species is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemeasurement capability for multiple gas speciesVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple optical cavities that would traditionally operate independently into a shared cavity system. Multiple laser sources targeting different spectral regions are coupled into a single optical cavity that contains a shared gas volume, allowing simultaneous measurement of multiple gas species while reducing the number of separate cavity assemblies needed

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shared optical cavity serves multiple functions by accommodating measurements for different gas species across different spectral regions. The single cavity structure is designed to be universal, handling what would traditionally require multiple specialized cavities, thereby simplifying the overall device architecture

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If cavity mirrors are designed for different spectral regions, then measurement of gases with different absorption lines is improved, but manufacturing cost increases

Engineering Contradiction:
Improvemeasurement of gases with different absorption linesVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The cavity mirrors are designed with universal spectral coverage rather than being specialized for specific wavelength regions. This allows a single set of mirrors to handle measurements across different spectral regions, eliminating the need to manufacture multiple sets of expensive specialized mirrors for different gas species

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple independent gas delivery systems are used for multiple cavities, then measurement of multiple gas species is improved, but system cost and complexity increase

Engineering Contradiction:
Improvemeasurement of multiple gas speciesVSAvoidsystem cost
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple independent gas delivery systems into a single shared gas delivery system. The shared gas volume is accessible to all laser sources through the same delivery infrastructure, eliminating redundant gas supply, pressure control, and flow management systems that would be required for multiple separate cavities

Inventive Principle:
Principle #5Merging (Combining)

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 enhances the precision and accuracy of gas analysis while reducing costs by allowing multiple gas species to be measured with a single optical cell or shared cavities, minimizing mechanical stress and temperature sensitivity.

Implementation Method 1

optical feedback assisted cavity enhanced absorption spectroscopy

Methodology Applied
Scientific EffectCavity enhanced absorption: Absorption (EM radiation)

Implementation Method 2

resonance optical cavity

Methodology Applied
Scientific EffectOptical resonance: Resonance

Implementation Method 3

combining two laser beams include using broadband beam splitters, using dichroic beam splitters or filters

Methodology Applied
Scientific EffectOptical beam splitting: Reflection

Implementation Method 4

locking the cavity to a molecular absorption line

Methodology Applied
Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Data Source

PatentEP3427025B1Multiple laser optical feedback assisted cavity enhanced absorption spectoscopy systems and methods
Publication Date: 2022.05.04 LI COR INC
  • EP3427025B1 patent drawingFigure 1
  • EP3427025B1 patent drawingFigure 1
  • EP3427025B1 patent drawingFigure 2

AI summary

Systems and methods for detecting trace gases utilize a resonance optical cavity and one, two or more coherent light sources coupled to the cavity through one or more cavity coupling mirrors, whereby two or more optical cavities may share the same gas volume.