Interferometer Spectral Dispersion Compensation via Angular Plate

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Solution Overview

Problem

Existing interferometer devices face challenges in fully compensating spectral dispersion, which leads to inaccurate spectral information due to varying optical path lengths caused by materials with wavelength-dependent refractive indices.

Innovation Solution

The method involves measuring spectral dispersion in an interferometer and compensating it by angularly positioning a dispersion compensation plate made of dispersive material, allowing for accurate equalization of optical path differences across all wavelengths of interest.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a beam splitter plate and compensating plate are used to minimize glass material thickness, then spectral dispersion is reduced, but thickness tolerances of +/-0.1mm cause optical path differences exceeding 50μm one way

Engineering Contradiction:
Improvespectral dispersionVSAvoidoptical path difference accuracy
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The invention makes the compensating plate angularly adjustable around an optical axis, transforming a static compensation system into a dynamic one. By rotating the plate to different angles, the optical path length through the dispersive material can be precisely controlled and optimized for each wavelength, compensating for manufacturing tolerances in plate thickness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the angular parameter of the compensating plate to optimize spectral dispersion compensation. By varying the angle of the compensating plate relative to the optical axis, the system can adjust the effective optical path difference to achieve wavelength-independent contact position, compensating for fixed manufacturing tolerances.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the index of refraction varies significantly with wavelength, then spectral information can be analyzed, but optical path length varies with wavelength making zero optical path difference impossible to achieve simultaneously for all wavelengths

Engineering Contradiction:
Improvespectral analysis capabilityVSAvoidcontact position accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The angular adjustability of the compensating plate allows dynamic optimization of the optical path for different wavelengths. By adjusting the angle, the system can achieve wavelength-independent contact position, ensuring precise spectral measurements across the entire spectral range.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from spectral measurements to determine the optimal angular position of the compensating plate. By analyzing the interferogram and identifying the contact position, the system can adjust the plate angle to achieve optimal compensation across all wavelengths.

Inventive Principle:
Principle #23Feedback

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 enables precise compensation of spectral dispersion, achieving optical path difference equality down to a fraction of a wavelength, thereby ensuring accurate spectral information acquisition over a large spectral range.

Implementation Method 1

compensating for spectral dispersion by angularly positioning a dispersion compensation plate of dispersive material with respect to an optical axis

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

The light reflected by both mirrors is combined on a detector to interfere

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP4560277A1A method and a device for spectral dispersion compensation in interferometers
Publication Date: 2025.05.28 UNITY SEMICONDUCTOR
  • EP4560277A1 patent drawingFigure 1(a)~2
  • EP4560277A1 patent drawingFigure 3~4(b)
  • EP4560277A1 patent drawingFigure 5

AI summary

The invention relates to a method (500) for acquiring an interference signal, comprising: - splitting an incident light wave into a first light wave and a second light wave propagating respectively in a first light path and a second light path of an interferometer, - adjusting an optical path difference between the first light wave and the second light wave, and - producing the interference signal by combining said first light wave and said second light wave on a detector, the method being characterized in that it further comprises: - measuring a spectral dispersion using the interference signal, and - compensating (505) said spectral dispersion by angularly positioning a dispersion compensation plate of dispersive material in a compensation angular position, with respect to an optical axis of the first light wave or the second light wave, to meet a spectral dispersion criterion. The invention further relates to an interferometer device implementing such a method.