Infrared Detector Plasmonic Resonator Thin Absorber
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Solution Overview
Problem
Current infrared detectors require cryogenic cooling due to sensitivity to thermal noise, and approaches focusing on either material design or volume reduction do not effectively achieve high enough operating temperatures for significant benefits.
Innovation Solution
A focal plane array infrared detector design incorporating a plasmonic resonator with a reduced thickness absorber layer, addressing both volume reduction and recombination mechanisms, allowing for higher operating temperatures by leveraging surface Plasmon resonance to improve quantum efficiency and reduce thermal noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the absorber layer thickness is reduced to decrease thermal noise sensitivity, then the detector can operate at higher temperatures, but the quantum efficiency decreases due to insufficient photon absorption
Solution Approach 1:
The patent employs surface plasmon resonance, which is an oscillatory electromagnetic phenomenon at the metal-dielectric interface, to concentrate and enhance the electromagnetic field within the thin absorber layer. This resonant field enhancement compensates for the reduced absorption path length, maintaining high quantum efficiency while enabling thinner absorber layers for reduced thermal noise
Solution Approach 2:
The patent modifies the optical parameters of the detector by introducing a plasmonic resonator structure with specific geometric parameters (grating period, ridge width, height) that are tuned to resonate at the detection wavelength. This parameter optimization enables enhanced light-matter interaction in the thin absorber layer, resolving the trade-off between thickness and absorption efficiency
2Volume of stationary object
If the absorber layer thickness is reduced to reduce thermal noise, then the detector volume decreases, but the absorption of incident radiation becomes insufficient
Solution Approach 1:
Surface plasmon resonance creates localized oscillating electromagnetic fields that dramatically enhance the absorption cross-section of the thin absorber layer. The resonant structure confines and intensifies the electromagnetic energy within the reduced-volume detector, enabling sufficient radiation absorption despite the smaller absorber thickness
Solution Approach 2:
The patent creates a composite structure combining metal (plasmonic material), dielectric (absorber layer), and semiconductor (collector layer) materials. This composite architecture leverages the unique optical properties of each material to achieve enhanced absorption in a compact volume, with the metal-dielectric interface providing field enhancement and the semiconductor layer providing charge collection
3Object-affected harmful factors
If cryogenic cooling is implemented to reduce thermal noise, then the detector sensitivity to thermal noise improves, but the device complexity and cost increase
Solution Approach 1:
The patent converts the harmful thermal noise into a beneficial design driver by accepting higher operating temperatures and compensating through plasmonic enhancement of the absorber. Instead of fighting thermal noise through cooling, the design embraces higher temperatures while using surface plasmon resonance to maintain sufficient signal generation, thereby eliminating complex cryogenic cooling systems
Solution Approach 2:
The patent replaces the mechanical/thermal cooling system with an optical field enhancement mechanism. Instead of using physical cooling to reduce thermal noise, the design uses electromagnetic field concentration via surface plasmon resonance to maintain detection capability at higher temperatures, substituting a complex thermal management system with an optical field control approach
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
The solution enables infrared detectors to operate at higher temperatures with reduced thermal noise and dark current, achieving up to two-fold improvement in performance by maintaining high quantum efficiency even with a thin absorber layer, thus eliminating the need for cryogenic cooling.
Implementation Method 1
a plasmonic resonator coupled to the collector layer and having a periodic structure including a plurality of features arranged in a regularly repeating pattern
Data Source
AI summary
Methods and structures for providing single-color or multi-color photo-detectors leveraging plasmon resonance for performance benefits. In one example, a radiation detector includes a semiconductor absorber layer having a first electrical conductivity type and an energy bandgap responsive to radiation in a first spectral region, a semiconductor collector layer coupled to the absorber layer and having a second electrical conductivity type, and a plasmonic resonator coupled to the collector layer and having a periodic structure including a plurality of features arranged in a regularly repeating pattern.