Spectrally Tuned Plasmonic Light Collectors for High-Efficiency Imaging
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Solution Overview
Problem
Conventional electronic devices with microlenses on silicon substrates have limited efficiency in transferring light to image sensors, requiring additional color elements and occupying space, which restricts the development of smaller devices and limits light absorption efficiency across various frequencies.
Innovation Solution
The use of plasmonic structures that generate high-intensity electromagnetic fields near the surface, allowing for the design of smaller image pixels with improved light absorption efficiency by configuring plasmonic image pixels to capture specific frequencies and reject others, utilizing patterned metal layers and reflective surfaces to trap and redirect light within the pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If microlenses and color filter elements are used in conventional imaging systems, then light absorption efficiency is improved, but device size increases and manufacturing complexity increases
Solution Approach 1:
The patent changes the fundamental optical parameters by replacing conventional microlens-based light collection with plasmonic structures that exploit surface plasmon resonance. This enables spectral tuning and enhanced light absorption without requiring additional color filter elements, thereby reducing pixel size while maintaining or improving light absorption efficiency.
Solution Approach 2:
The patent substitutes the mechanical/optical system of microlenses and color filters with a plasmonic electromagnetic field-based system. The plasmonic structures generate high-intensity electromagnetic fields that directly interact with incident light, eliminating the need for mechanical microlens assemblies and reducing structural complexity.
2Reliability
If microlenses and color filter elements are used in conventional imaging systems, then light absorption efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of light collection, spectral filtering, and light absorption enhancement into a single plasmonic structure. The patterned metal layers and dielectric materials work together to simultaneously perform multiple optical functions that were previously required separate components (microlenses and color filters).
Solution Approach 2:
The plasmonic structures serve multiple functions: they act as light collectors, spectral filters, and absorption enhancers simultaneously. By tuning the plasmonic resonance conditions through pattern design, the same structure can be optimized for different wavelengths and applications, providing universal functionality across the electromagnetic spectrum.
3Illumination intensity
If conventional microlens structures are used, then light focusing is achieved, but spectral selectivity is limited
Solution Approach 1:
The patent exploits the tunable nature of plasmonic resonance by changing geometric parameters of the patterned metal layers and dielectric materials. This enables precise control over the resonant wavelength and spectral response, allowing the same basic structure to be adapted for different spectral regions from ultraviolet to infrared.
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 increases light absorption efficiency, enabling the development of smaller electronic devices with improved imaging systems that can capture a broader range of frequencies with higher efficiency compared to conventional systems.
Implementation Method 1
Plasmonic effects are quantum surface field effects in which an evanescent wave of electron density oscillations is generated on or near a surface of a metal or meta-material in response to incoming, incident light. In structures designed to exhibit plasmonic effects, incoming photons incident on the plasmonic structure generate plasmons associated with high intensity electromagnetic fields within nano-scale distances from the surface of the structure.
Data Source
AI summary
Electronic devices may be provided with imaging modules that include plasmonic light collectors. Plasmonic light collectors may be configured to exploit an interaction between incoming light and plasmons in the plasmonic light collector to alter the path of the incoming light. Plasmonic light collectors may include one or more spectrally tuned plasmonic image pixels configured to preferentially trap light of a given frequency. Spectrally tuned plasmonic image pixels may include plasmonic structures formed form a patterned metal layer over doped silicon layers. Doped silicon layers may be interposed between plasmonic structures and a reflective layer. Plasmonic image pixels may be used to absorb and detect as much as, or more than, ninety percent of incident light at wavelengths ranging from the infrared to the ultraviolet. Plasmonic image pixels that capture light of different colors may be arranged in patterned arrays to form imager modules or imaging spectrometers for optofluidic microscopes.