Spectrometer Using Plasmonic Filter Array for Miniaturization
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Solution Overview
Problem
Conventional spectrometers face challenges in miniaturization, process reproducibility, resolution limitations, and material constraints, particularly in the mid-infrared wavelength band, due to the linear structure of linear variable filters and interference filters, which hinder two-dimensional integration and broadband operation.
Innovation Solution
A spectrometer design utilizing a spectral filter array with unit spectral filters having stop band characteristics, composed of periodically arranged metal patterns, which absorb or reflect specific wavelength bands, allowing for two-dimensional integration and improved durability, and a processing unit to restore the target light spectrum from detected signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a linear variable filter (LVF) with linear structure is used, then the spectrometer can be miniaturized, but the process reproducibility deteriorates and two-dimensional integration becomes difficult
Solution Approach 1:
The spectral filtering function is segmented into multiple discrete unit spectral filters arranged in an array, where each filter handles a specific wavelength band. This segmentation allows each filter to be manufactured independently with consistent quality, improving process reproducibility while maintaining compact size through two-dimensional arrangement.
Solution Approach 2:
The filter array transitions from a one-dimensional linear structure to a two-dimensional arrangement, allowing spectral filtering to be achieved through spatial distribution in both horizontal and vertical directions. This dimensional change enables better integration with two-dimensional detector arrays and improves manufacturing consistency.
2Adaptability or versatility
If conventional interference filters are used, then the spectrometer can operate in mid-infrared band, but the material selection is limited and thermal stability deteriorates
Solution Approach 1:
The spectral filters are constructed using composite material systems combining metal patterns (such as gold, silver, or aluminum) with dielectric layers. This composite structure enables simultaneous achievement of desired optical filtering characteristics in mid-infrared band and improved thermal stability, as the metal-dielectric combination provides both plasmonic resonance control and thermal resistance.
3Measurement precision
If Fabry-Perot filter with multiple dielectric resonance layers is used, then the wavelength filtering can be achieved, but the number of litho process steps increases and manufacturing complexity deteriorates
Solution Approach 1:
The complex multi-layer dielectric resonance structure is replaced by extracting and utilizing plasmonic resonance from metal patterns. This extraction of the core resonant function to a simpler metal-pattern-based structure reduces the number of lithography steps and manufacturing complexity while maintaining wavelength filtering precision through plasmonic resonance control.
4Volume of moving object
If LVF with linear structure is used, then the spectrometer can be compact, but the resolution is limited by height-to-length ratio and further downsizing becomes difficult
Solution Approach 1:
The spectral resolution is improved by utilizing two-dimensional spatial distribution of filters instead of one-dimensional linear arrangement. This allows the spectrometer to achieve high resolution without increasing the height-to-length ratio, enabling further miniaturization while maintaining or improving spectral resolution through optimized two-dimensional filter positioning.
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 a compact, cost-effective spectrometer with a broad operational range covering near-infrared and infrared bands, enhanced signal restoration capability, and improved reliability with materials exhibiting plasmonic characteristics and excellent thermal stability.
Implementation Method 1
periodically arranged metal patterns, which absorb or reflect specific wavelength bands, allowing for two-dimensional integration and improved durability
Implementation Method 2
unit spectral filters having stop band characteristics, composed of periodically arranged metal patterns, which absorb or reflect specific wavelength bands
Implementation Method 3
unit spectral filters having stop band characteristics, composed of periodically arranged metal patterns, which absorb or reflect specific wavelength bands
Implementation Method 4
spectral filter array with unit spectral filters having stop band characteristics
Implementation Method 5
unit spectral filters having stop band characteristics, composed of periodically arranged metal patterns, which absorb or reflect specific wavelength bands
Implementation Method 6
a processing unit to restore the target light spectrum from detected signals
Implementation Method 7
improved reliability with materials exhibiting plasmonic characteristics and excellent thermal stability
Data Source
AI summary
Present invention provides a spectrometer including a first unit spectral filter configured to absorb or reflect light in a part of a wavelength band of a light spectrum of an incident target, a second unit spectral filter configured to absorb or reflect light in a wavelength band different from the part of the wavelength band, a first light detector configured to detect a first light spectrum passing through the first unit spectral filter, a second light detector configured to detect a second light spectrum passing through the second unit spectral filter, and a processing unit configured to perform a function of restoring a light spectrum of the target incident from spectra of light detected from the first light detector and the second light detector.