Multi-pixel Spectral Sensor Using Resonant Cavity Photodetectors
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Solution Overview
Problem
Current spectral sensor systems are large, complex, and expensive, making them challenging to miniaturize for integration with small handheld devices, particularly in the near-infrared range where cost-effective detectors and imaging arrays are lacking, limiting their spectral range and resolution.
Innovation Solution
A multi-pixel spectral sensor with an array of resonant-cavity photodetector elements, each comprising reflective layers and a phase tuning material, configured for different wavelength responses, allowing for simultaneous read-out of photocurrents to reconstruct the spectrum, which can be used with machine learning algorithms for material identification without the need for spectral reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional spectral sensor systems are used, then spectral analysis capability is achieved, but device size and complexity increase
Solution Approach 1:
The spectrometer is divided into multiple pixel elements, each with its own photodetector and phase tuning element. Each pixel element independently processes a specific portion of the spectral range, eliminating the need for large optical components while maintaining spectral analysis capability through parallel detection across the pixel array.
Solution Approach 2:
The patent transitions from sequential spectral measurement (single detector scanning through wavelengths) to parallel spatial-spectral measurement (multiple pixels detecting different wavelengths simultaneously). This dimensional change from 1D spectral scanning to 2D spatial-spectral detection enables miniaturization by removing the need for moving parts and large optical paths.
2Length of moving object
If spectral sensor systems are miniaturized, then device size is reduced, but spectral range and resolution are limited
Solution Approach 1:
Each pixel element is equipped with a phase tuning element that can be independently configured to respond to specific wavelength ranges. This local customization of spectral response allows the compact sensor array to collectively cover a broad spectral range with high resolution, as each pixel optimizes detection for its assigned wavelength band.
Solution Approach 2:
The phase tuning elements can dynamically adjust their resonant frequencies to change the spectral response characteristics of each pixel. This parameter tuning capability allows the miniaturized sensor to adapt its spectral range and resolution settings, maintaining high measurement precision across different operating conditions despite the reduced device size.
3Adaptability or versatility
If near-infrared spectral detection is implemented, then spectral range is extended, but detector cost and complexity increase
Solution Approach 1:
The sensor uses an array of standard photodetectors that can detect visible light, combined with phase tuning elements that extend the effective spectral range into the near-infrared. This universal approach allows the same detector architecture to handle multiple spectral ranges by tuning the phase elements, avoiding the need for expensive specialized near-infrared detectors while maintaining extended spectral capability.
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 a compact, low-cost spectral sensor with improved resolution and robustness, capable of direct material identification and classification, suitable for integration with smartphones and other small devices, and can be used in various applications including food quality monitoring and agriculture.
Implementation Method 1
a detector element comprising a layer of photo active material arranged to define a photodetector, the photodetector being arranged to convert light of the set of wavelengths defined by the corresponding phase tuning element into a photocurrent
Implementation Method 2
a phase tuning element, comprising a phase tuning material configured for resonant response to a defined set of wavelengths of the light
Implementation Method 3
a first reflective structure, comprising one or more layers of reflective material; a second reflective structure, comprising one or more layers of reflective material, wherein the first and second reflective structures are arranged for reflecting the light from the sample
Data Source
AI summary
A multi-pixel spectroscopy sensor for spectral analysis of a sample under test including an array of pixel elements generating a dataset including a plurality of data values corresponding to the pixel elements upon illumination of the sample by a light source. Each of the pixel elements including a stack of layers including first and second reflective structures, a phase tuning element, a detector element, and contact elements. The sensor further includes a read-out circuit connected to each of the contact elements for simultaneous read-out of a plurality of photocurrents for generating and outputting the dataset for the spectral analysis of the sample under test. The phase tuning element of each of the pixel elements is configured for a different wavelength response of the light and each photodetector of the pixel elements is comprised of a semiconductor material.