Infrared Detector Meta-Surface for Pixel Crosstalk Reduction
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Solution Overview
Problem
Current infrared imaging technologies face challenges with crosstalk between pixels, degradation of the transfer function, and the complexity of aligning and manufacturing microlenses, particularly in hybrid-type matrix optical detectors using III-V materials, which affect the performance and precision of infrared imaging.
Innovation Solution
The integration of dielectric resonators, or Huygens meta-surfaces, within the detector structure to enhance light concentration and reduce crosstalk, while allowing for improved optical function and reduced pixel size, by configuring the resonators to resonate at specific wavelengths and account for the position of each pixel in the detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microlenses are used to improve light concentration and reduce crosstalk, then optical performance is improved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent removes microlenses from the detector structure entirely, replacing them with a planar meta-surface composed of sub-wavelength resonators. This extraction eliminates the alignment complexity between microlenses and pixels while maintaining optical concentration functionality through resonant coupling between the meta-surface and the photodiode antenna.
Solution Approach 2:
The patent replaces the mechanical optical system (microlenses requiring precise physical alignment) with an electromagnetic resonant system (meta-surface with sub-wavelength resonators). The optical concentration is achieved through resonant coupling and phase modulation rather than mechanical focusing, thereby eliminating alignment complexity.
2Measurement precision
If pixel size is reduced to increase detector resolution, then imaging precision is improved, but crosstalk between pixels increases
Solution Approach 1:
The patent implements local quality by designing pixel-specific resonator configurations within the meta-surface. Each pixel region has tailored resonators with specific geometries, sizes, and orientations that are optimized for local light concentration and phase control, enabling reduced pixel size while maintaining signal isolation and reducing crosstalk through localized resonant coupling.
3Ease of manufacture
If conventional photodiode structures are used, then manufacturing is simpler, but optical efficiency and sensitivity are limited
Solution Approach 1:
The patent employs composite material structures by integrating a meta-surface layer with sub-wavelength resonators made of dielectric or metallic materials with the photodiode substrate. This composite structure combines the optical resonance properties of the meta-surface with the electrical detection capabilities of the photodiode, achieving enhanced optical efficiency while maintaining compatibility with standard semiconductor manufacturing processes.
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 significantly reduces optical and electrical crosstalk, enhances sensitivity, and allows for smaller pixel sizes while maintaining sensitivity, through the precise control of light focusing and phase modulation, thereby improving the overall performance of the infrared imaging system.
Implementation Method 1
each resonator being configured to resonate at specific wavelengths and account for the position of each pixel in the detector
Implementation Method 2
enhance light concentration and reduce crosstalk, while allowing for improved optical function
Implementation Method 3
an absorbent layer of III-V or II-VI semiconductor material called active material, capable of photogenerating carriers by absorption of light incident on said detector
Data Source
Figure 1a~1b
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AI summary
The invention concerns a hybrid-type optical detector (10) comprising a stack along a Z-axis comprising: - an absorbent structure (Sabs) sensitive in a wavelength band of interest (SB), said structure comprising at least: - one absorbent layer (AL) made of lll-V or ll-VI semiconductor material, termed active material, - an upper layer (Lsup) made of a lll-V or IV semiconductor material, - the absorbent structure further comprising, in at least one layer, a plurality of doped zones (DZ), - a reading circuit (ROIC) comprising a plurality of embedded contacts (TLC), - the absorbent structure (Sabs) and the reading circuit (ROIC) being assembled by an assembly layer (11) in order to form the optical detector (10), - the hybrid detector further comprising an assembly of dielectric resonators (Res) etched in the upper layer (Lsup) and forming an upper surface (Ssup), each resonator being configured to scatter, in a resonant manner, when illuminated by the incident light, a light having at least one resonance wavelength (λR) included in the wavelength band of interest (SB).