Planar Spectral Filter Dispersion for Complex Light Analysis
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Solution Overview
Problem
Conventional Fabry-Perot spectrometers are limited in analyzing diffuse or spectrally complex light sources due to radially symmetric spatial patterns and the free spectral range, which causes degeneracy and prevents the differentiation of spatial patterns corresponding to different wavelengths.
Innovation Solution
A planar spectral filter optical spectrometer with a dispersion system and a two-dimensional detector array, where the dispersion system disperses spatial patterns along at least one dimension, preventing overlap and creating an asymmetric image that allows for multi-dimensional sampling and overcoming the free spectral range limitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Fabry-Perot filter is used to generate spatial interference patterns, then the spectrometer can measure wavelength-specific properties, but the radially symmetric spatial patterns create degeneracy that prevents analysis of spectrally complex sources
Solution Approach 1:
The patent applies asymmetry by using a dispersion system to break the radial symmetry of the Fabry-Perot spatial patterns. The dispersion system shifts the center positions of different wavelength patterns along a dispersion direction, transforming the radially symmetric patterns into asymmetric patterns with distinct spatial locations. This allows the spectrometer to distinguish between different wavelengths in spectrally complex sources, resolving the degeneracy problem while maintaining wavelength-specific measurement precision.
Solution Approach 2:
The patent introduces an additional spatial dimension through the dispersion system. Instead of relying solely on radial symmetry in two dimensions, the dispersion system adds a third dimension (dispersion direction) to separate wavelengths spatially. This dimensional expansion allows patterns corresponding to different wavelengths to be distinguished by their positions along the dispersion axis, enabling analysis of spectrally complex sources without losing wavelength-specific measurement capability.
2Reliability
If the free spectral range of the Fabry-Perot filter is used, then the filter can operate within a specific wavelength range, but integer multiples of the free spectral range create overlapping spatial patterns that cause degeneracy
Solution Approach 1:
The dispersion system introduces asymmetry that shifts the spatial patterns of different wavelengths in the dispersion direction. This asymmetric shift prevents patterns corresponding to integer multiples of the free spectral range from overlapping, as each pattern is displaced to a unique position along the dispersion axis. The asymmetry breaks the periodic degeneracy while maintaining the filter's reliable operation within its specified wavelength range.
Solution Approach 2:
The dispersion system acts as an intermediary between the Fabry-Perot filter and the detector array. It processes the spatial patterns generated by the filter by dispersing them in a wavelength-dependent manner, preventing direct overlap of patterns from different wavelength ranges. This intermediary function preserves the filter's operational reliability while eliminating the information loss caused by pattern degeneracy.
3Device complexity
If conventional Fabry-Perot spectrometer design is used, then the device structure is simple, but it cannot differentiate spatial patterns of different wavelengths from diffuse or spectrally complex sources
Solution Approach 1:
The dispersion system serves as an intermediary component added to the conventional Fabry-Perot spectrometer design. It sits between the filter and detector array, processing the spatial patterns by dispersing them according to wavelength. This additional intermediary element enables wavelength differentiation in spectrally complex sources while maintaining the relative simplicity of the overall device structure, as the dispersion system can be implemented using standard optical components.
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 the analysis of spectrally complex sources by preventing spatial pattern overlap and allowing processor to distinguish patterns across a wide spectral range, enhancing the capability to analyze diffuse or complex light sources.
Implementation Method 1
The filter generates a spatial interference pattern based on the incident light from the source
Implementation Method 2
The dispersion system disperses the spatial patterns along at least one dimension in a wavelength dependent fashion onto the detector array
Data Source
AI summary
An optical spectrometer and/or a method of optical spectroscopy is described herein. One exemplary spectrometer includes a planar spectral filter, a dispersion system, and a detector array having at least two dimensions. The planar spectral filter filters incident light to generate a plurality of wavelength dependent spatial patterns. The dispersion system disperses the spatial patterns along at least one dimension in a wavelength dependent fashion onto the detector array. As a result, spatial patterns corresponding to different wavelengths are centered at different locations on the detector array. The dispersed spatial patterns superimpose at the detector array in an offset but overlapping relationship, creating an asymmetric image that facilitates the spectral analysis of a wide range of light sources, including diffuse or spectrally complex light sources.