Wavelength Selective Detector Using Pore-Based Photonic Crystal Filters
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Solution Overview
Problem
Conventional wavelength selective photodetectors lack sufficient detection accuracy due to their inability to differentiate between various wavelengths of electromagnetic radiation effectively.
Innovation Solution
A device and method utilizing a substrate with pores of varying physical parameters, such as diameter and depth, to act as wavelength-specific filters, where electromagnetic radiation propagates through the pores before reaching a photodiode, allowing for precise detection of different wavelength ranges by exploiting diffraction effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional wavelength selective photodetectors are used, then the device structure is simple, but the detection accuracy is insufficient
Solution Approach 1:
The patent employs a porous layer with controlled pore sizes (ranging from 50nm to 500nm) formed on the substrate surface. These pores act as wavelength-selective filters through diffraction effects, where each pore size corresponds to specific wavelength ranges. The porous structure enables accurate wavelength differentiation without requiring complex multi-layer interference filters or grating systems, thus improving detection accuracy while maintaining relatively simple device architecture.
Solution Approach 2:
The patent implements spatially varying pore sizes across different regions of the porous layer. Specific pore size ranges are localized to detect specific wavelength ranges (e.g., 50-150nm pores for UV, 150-300nm for visible, 300-500nm for infrared). This local differentiation of pore quality allows the single photodiode to selectively detect different wavelengths by controlling which pore sizes the radiation passes through, achieving wavelength-selective detection without complex spectral splitting optics.
2Adaptability or versatility
If multiple wavelength detectors are integrated, then wavelength detection capability is improved, but the device size increases
Solution Approach 1:
The patent makes a single photodiode perform multiple wavelength detection functions by placing a porous wavelength-selective layer in front of it. The porous layer with its distribution of different pore sizes acts as an integrated spectral filter that directs different wavelength ranges to the same detector. This multi-functional approach allows one photodiode to detect multiple wavelength ranges (UV, visible, infrared) simultaneously, eliminating the need for multiple separate detectors and reducing overall device size.
Solution Approach 2:
The patent transitions from spatial separation of wavelength detectors (requiring multiple detectors arranged in space) to a depth-dimension solution using a vertically structured porous layer. The pore size selection occurs in the vertical dimension of the porous layer, allowing wavelength selection without lateral expansion. Radiation passes through the porous layer at normal incidence, and wavelength selection is achieved through the depth-dependent pore structure rather than lateral positioning, thus maintaining compact device footprint.
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 accurate detection of electromagnetic radiation across specific wavelength ranges with high precision and efficiency, enabling the creation of small, reliable, and cost-effective wavelength detectors for applications like solid-state lighting control and feedback loops.
Implementation Method 1
wherein different ones of the plurality of pores differ regarding at least one physical parameter so that each of the plurality of pores is sensitive to an assigned wavelength range of electromagnetic radiation
Data Source
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AI summary
A device (100) for detecting electromagnetic radiation, the device (100) comprising a substrate (102), an electromagnetic radiation sensitive structure (104) arranged on and/or in the substrate (102), and a plurality of pores (106) formed on and/or in the substrate (102) in such a manner that electromagnetic radiation to be detected propagates through at least a part of the plurality of pores (106) before propagating into the electromagnetic radiation sensitive structure (104), wherein different ones of the plurality of pores (106) differ regarding at least one physical parameter so that each of the plurality of pores (106) is sensitive to an assigned wavelength range of electromagnetic radiation.