Photothermal Mid-Infrared Detection With Silicon Sensors
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Solution Overview
Problem
Mid-infrared light optical sensors are more expensive and less sensitive than silicon sensors, limiting their use in high-sensitivity applications, particularly in detecting light power smaller than pW, and require improvements in function and performance.
Innovation Solution
A photothermal effect-based mid-infrared detecting apparatus is developed by coating an optical sensor with a material that absorbs mid-infrared light, such as graphene or carbon nanotubes, to generate heat, which is then detected using a processor that analyzes the sensor signal modulated by this heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mid-infrared light optical sensor is used, then the sensor can detect mid-infrared light, but the sensor is more expensive and has lower sensitivity than a silicon sensor
Solution Approach 1:
The patent introduces a photothermal converter layer as an intermediary substance between the mid-infrared light source and the silicon optical sensor. This converter absorbs mid-infrared light and converts it to heat, which then modulates the signal detected by the silicon sensor, enabling indirect detection of mid-infrared light with high sensitivity
Solution Approach 2:
The patent replaces the direct optical detection mechanism with a photothermal conversion mechanism. Instead of using a specialized mid-infrared sensor that directly detects photons, the system uses a silicon sensor that detects heat-induced signal modulation, substituting optical detection with thermal detection
2Adaptability or versatility
If a mid-infrared light optical sensor is used, then the sensor can detect mid-infrared light, but the cost is higher than using a silicon sensor
Solution Approach 1:
The patent makes the silicon optical sensor multi-functional by adding the photothermal converter layer. The same silicon sensor can now detect both visible light and mid-infrared light (through photothermal conversion), eliminating the need for separate specialized sensors and reducing overall system cost
Solution Approach 2:
The patent uses inexpensive materials for the photothermal converter layer, such as carbon-based materials or metal films, which can be deposited as thin layers. These inexpensive converter layers enable the use of cheap silicon sensors instead of expensive specialized mid-infrared sensors
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 apparatus enables detection of mid-infrared light at a single photon level with improved sensitivity and reduced cost, allowing for applications in fields like chemical and biological detection, environmental monitoring, and alcohol detection.
Implementation Method 1
an infrared light layer disposed on the optical sensor and comprising a material that absorbs a mid-infrared light... the optical sensor receives heat generated by the mid-infrared light incident on the infrared light layer
Data Source
AI summary
The present invention relates to a photothermal effect-based mid-infrared detecting apparatus including an optical sensor that detects visible light, an infrared light layer disposed on the optical sensor and including a material that absorbs a mid-infrared light, and a processor that detects the mid-infrared light by analyzing a sensor signal output from the optical sensor, wherein the optical sensor receives heat generated by the mid-infrared light incident on the infrared light layer and outputs the sensor signal modulated by the heat to the processor.