Multi-Channel Up-Conversion Infrared Spectrometer

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Solution Overview

Problem

Current infrared spectrometers face challenges with low-noise detection due to thermal background radiation and require high precision mechanical systems and cryogenic cooling, limiting their efficiency and cost-effectiveness, especially in scanning and wavelength range coverage.

Innovation Solution

The development of an infrared spectrometer with multiple up-conversion channels that convert infrared radiation to shorter wavelengths, allowing for detection with available detectors and reducing mechanical tolerances and cooling requirements, using nonlinear materials and demultiplexing techniques to cover an extended wavelength range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single up-conversion channel is used, then the device complexity is reduced, but the wavelength range coverage is limited

Engineering Contradiction:
Improvewavelength range coverageVSAvoidnumber of up-conversion channels
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spectrometer divides the broad wavelength range detection task into multiple segmented up-conversion channels, each optimized for specific wavelength ranges. This segmentation allows the system to cover a broader spectrum by combining results from multiple specialized channels rather than using a single general-purpose channel.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each up-conversion channel is designed to handle multiple wavelength ranges through adjustable phase-matching conditions, making the channels multi-functional. The system achieves universal wavelength coverage by having each channel capable of operating across different spectral regions.

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

2Adaptability or versatility

If temperature tuning is used to phase-match different wavelength ranges, then the wavelength range is extended, but the acquisition time increases to minutes

Engineering Contradiction:
Improvewavelength rangeVSAvoidacquisition time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system dynamically adjusts phase-matching conditions for each up-conversion channel to optimize detection for different wavelength ranges. This dynamic adaptation allows rapid switching between wavelength ranges without the slow thermal equilibration required by temperature tuning methods.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes operational parameters (such as crystal orientation, beam angle, or mixing laser wavelength) to achieve phase-matching for different wavelength ranges, avoiding the need for slow temperature changes. This parameter adjustment approach enables rapid wavelength range switching while maintaining detection accuracy.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If cryogenically cooled detectors are used, then the signal-to-noise ratio is improved, but the operating cost and device complexity increase

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoidcooling system requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention replaces the mechanical cooling system with an optical frequency conversion approach. By converting infrared radiation to visible or near-infrared wavelengths through non-linear optical processes, the system enables detection using room-temperature detectors, eliminating the need for complex cryogenic cooling infrastructure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The up-conversion crystal acts as an intermediary that transforms the infrared signal into a form detectable by room-temperature detectors. This intermediary conversion process preserves the signal information while changing its wavelength, allowing high signal-to-noise detection without cryogenic cooling.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If high precision mechanical scanning systems are used, then the measurement precision is improved, but the cost and vibration sensitivity increase

Engineering Contradiction:
Improvespectral resolutionVSAvoidmechanical scanning system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention replaces mechanical scanning systems with a multi-channel optical detection approach. By using multiple up-conversion channels with different phase-matching conditions, the system achieves spectral resolution through optical means rather than mechanical positioning, eliminating vibration sensitivity and reducing mechanical complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 improves signal-to-noise performance and reduces acquisition time for spectral measurements, enabling cost-effective and vibration-tolerant infrared spectrometry without the need for cryogenic cooling, while covering a broader wavelength range efficiently.

Implementation Method 1

frequency up-conversion of the infrared radiation to shorter wavelengths

Methodology Applied
Scientific EffectFrequency up-conversion: Second Harmonic Generation

Implementation Method 2

up-conversion of the infrared radiation using a nonlinear crystal

Methodology Applied
Scientific EffectNonlinear optical conversion: Second Harmonic Generation

Implementation Method 3

the phase-matching condition of the nonlinear material is generally dependent on an angle of the incoming radiation relative to an optical axis of the nonlinear material

Methodology Applied
Scientific EffectPhase-matching:

Data Source

PatentEP3019912B1Multi-channel up-conversion infrared spectrometer and method of detecting a spectral distribution of light
Publication Date: 2017.08.30 DANMARKS TEKNISKE UNIV
  • EP3019912B1 patent drawingFigure 1~4
  • EP3019912B1 patent drawingFigure 5~8
  • EP3019912B1 patent drawingFigure 9a~9c

AI summary

A multi-channel infrared spectrometer for detecting an infrared spectrum of light received from an object. The spectrometer comprises a wavelength converter system comprising a nonlinear material and having an input side and an output side. The wavelength converter system comprises at least a first up-conversion channel and a second up-conversion channel, and is arranged such that light traversing the wavelength converter system at different angles in the nonlinear material is imaged into different positions in an image plane. The first up- conversion channel is configurable for phase-matching infrared light in a first input wavelength range incident on the first side and light in a first output wavelength range output on the second side, and correspondingly, the second up-conversion channel is configurable for phase-matching infrared light in a second input wavelength range incident on the first side into light in a second output wavelength range output on the second side. The spectrometer further comprises a demultiplexer configured for demultiplexing light in the first up-conversion channel and light in the second up-conversion channel. The demultiplexer is located on the first side or the second side of the wavelength converter system. Finally, the spectrometer comprises a spatially resolved detector arranged in the image plane to detect light in the first output wavelength range and second output wavelength range output of the wavelength converter system.